{"id":309,"date":"2026-09-29T10:06:12","date_gmt":"2026-09-29T17:06:12","guid":{"rendered":"https:\/\/hostandtech.com\/kb\/?p=309"},"modified":"2026-09-29T10:06:12","modified_gmt":"2026-09-29T17:06:12","slug":"plesk-windows-503-service-unavailable-application-pool","status":"publish","type":"post","link":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/","title":{"rendered":"Plesk Windows 503 Service Unavailable: Fix a Stopped Application Pool"},"content":{"rendered":"<h2>Overview<\/h2>\n<p>A 503 Service Unavailable on a website hosted in Plesk for Windows almost always means the site&#8217;s IIS application pool has stopped. Restart it in Plesk under <strong>Websites &amp; Domains &gt; your domain &gt; Dedicated IIS Application Pool for Website<\/strong> (Switch Off, then Switch On), or run <code class=\"\" data-line=\"\">plesk repair web example.com -y<\/code> from an elevated prompt on the server. If it stops again, one of two things is behind it: the app keeps crashing, or the pool&#8217;s Windows user has a bad password.<\/p>\n<p>This guide is for admins of Plesk Obsidian on Windows Server (a VPS, dedicated server or your own machine) who see a bare &#8220;Service Unavailable&#8221; page or <code class=\"\" data-line=\"\">HTTP Error 503. The service is unavailable.<\/code> You&#8217;ll restart the pool, read the Event Viewer entry that names the real cause, and apply the matching fix. Allow about 15 minutes.<\/p>\n<h2>What causes the 503 in Plesk for Windows<\/h2>\n<p>Plesk gives each website its own IIS application pool, named after the domain. When a pool isn&#8217;t running, IIS answers every request with 503 and nothing appears in the domain&#8217;s error log, which is why people chase the wrong thing. The pool state and the Windows System log hold the answer. The three usual causes:<\/p>\n<ul>\n<li><strong>The pool stopped unexpectedly<\/strong> and nobody restarted it (a recycle failure, a reboot race, a manual stop in IIS Manager).<\/li>\n<li><strong>Rapid-Fail Protection tripped.<\/strong> IIS disables a pool after repeated crashes; the default is 5 failures within 5 minutes.<\/li>\n<li><strong>The pool identity is broken.<\/strong> The Windows user Plesk created for the site has a password the pool no longer knows.<\/li>\n<\/ul>\n<h2>How to fix it<\/h2>\n<h3>Fix 1: Restart the application pool<\/h3>\n<ol>\n<li>Log in to Plesk and open <strong>Websites &amp; Domains<\/strong> (called <strong>Domains<\/strong> in older versions).<\/li>\n<li>Under the affected domain, click <strong>Dedicated IIS Application Pool for Website<\/strong>.<\/li>\n<li>Click <strong>Switch Off<\/strong>, wait a few seconds, then <strong>Switch On<\/strong>.<\/li>\n<\/ol>\n<figure class=\"wp-block-image\"><img src=\"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/09\/plesk-windows-app-pool-path.webp\" alt=\"Diagram of the Plesk path Websites and Domains, the domain, Dedicated IIS Application Pool for Website, then Switch Off and Switch On\" width=\"1000\" height=\"760\" loading=\"lazy\" decoding=\"async\"><figcaption>Restarting a site&#8217;s application pool from Plesk Obsidian.<\/figcaption><\/figure>\n<p>Reload the site. If it comes back, wait ten minutes and reload again to be sure the pool stays up. If Plesk&#8217;s panel isn&#8217;t reachable, connect by <a href=\"https:\/\/hostandtech.com\/kb\/windows-server\/how-to-configure-remote-desktop-rdp-windows-server\/\">Remote Desktop<\/a>, open an elevated command prompt or PowerShell, and rebuild the site&#8217;s web configuration:<\/p>\n<div class='ht-code-snippet'><button class='ht-code-snippet__copy' onclick='htCopyCode(\"code-block-1\")' type='button' aria-label='Copy code'><svg class='ht-copy-icon' viewBox='0 0 32 32' width='16' height='16' fill='currentColor'><path d='M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z'><\/path><path d='M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z'><\/path><\/svg><svg class='ht-check-icon' viewBox='0 0 32 32' width='16' height='16' fill='currentColor'><path d='M13,24l-9-9,1.414-1.414L13,21.171,26.586,7.586,28,9Z'><\/path><\/svg><\/button><span class='ht-code-snippet__feedback'>Copied to clipboard<\/span><\/p>\n<pre class='ht-code-snippet__code' id='code-block-1'><code class=\"\" data-line=\"\">plesk repair web example.com -y<\/code><\/pre>\n<\/div>\n<p>To check or start the pool without opening IIS Manager, this works in an elevated PowerShell window (the pool name is the domain name):<\/p>\n<div class='ht-code-snippet'><button class='ht-code-snippet__copy' onclick='htCopyCode(\"code-block-2\")' type='button' aria-label='Copy code'><svg class='ht-copy-icon' viewBox='0 0 32 32' width='16' height='16' fill='currentColor'><path d='M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z'><\/path><path d='M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z'><\/path><\/svg><svg class='ht-check-icon' viewBox='0 0 32 32' width='16' height='16' fill='currentColor'><path d='M13,24l-9-9,1.414-1.414L13,21.171,26.586,7.586,28,9Z'><\/path><\/svg><\/button><span class='ht-code-snippet__feedback'>Copied to clipboard<\/span><\/p>\n<pre class='ht-code-snippet__code' id='code-block-2'><code class=\"\" data-line=\"\">Import-Module WebAdministration; Get-WebAppPoolState -Name example.com; Start-WebAppPool -Name example.com<\/code><\/pre>\n<\/div>\n<h3>Fix 2: Read the Event Viewer entry that says why it stopped<\/h3>\n<p>A restart hides the cause, so look before you forget. Open <strong>Event Viewer &gt; Windows Logs &gt; System<\/strong> and find entries from the source <strong>WAS<\/strong> around the time of the outage. Or list them in one line:<\/p>\n<div class='ht-code-snippet'><button class='ht-code-snippet__copy' onclick='htCopyCode(\"code-block-3\")' type='button' aria-label='Copy code'><svg class='ht-copy-icon' viewBox='0 0 32 32' width='16' height='16' fill='currentColor'><path d='M28,10V28H10V10H28m0-2H10a2,2,0,0,0-2,2V28a2,2,0,0,0,2,2H28a2,2,0,0,0,2-2V10a2,2,0,0,0-2-2Z'><\/path><path d='M4,18H2V4A2,2,0,0,1,4,2H18V4H4Z'><\/path><\/svg><svg class='ht-check-icon' viewBox='0 0 32 32' width='16' height='16' fill='currentColor'><path d='M13,24l-9-9,1.414-1.414L13,21.171,26.586,7.586,28,9Z'><\/path><\/svg><\/button><span class='ht-code-snippet__feedback'>Copied to clipboard<\/span><\/p>\n<pre class='ht-code-snippet__code' id='code-block-3'><code class=\"\" data-line=\"\">Get-WinEvent -FilterHashtable @{LogName=&#039;System&#039;; ProviderName=&#039;Microsoft-Windows-WAS&#039;} -MaxEvents 20 | Format-List TimeCreated, Id, Message<\/code><\/pre>\n<\/div>\n<p>The message tells you which fix applies. &#8220;Application pool &#8216;example.com&#8217; is being automatically disabled due to a series of failures&#8221; points to Fix 3. A message about the identity, user name or password, or &#8220;batch logon rights&#8221;, points to Fix 4.<\/p>\n<h3>Fix 3: Rapid-Fail Protection keeps disabling the pool<\/h3>\n<p>This means the site&#8217;s worker process crashes over and over. The pool stopping is a symptom. Open <strong>Event Viewer &gt; Windows Logs &gt; Application<\/strong> and look for <strong>Event ID 1026<\/strong> (.NET runtime) or <strong>1000<\/strong> (application error) at the same times. Those entries hold the exception and the faulting module, usually a bad deployment, a missing runtime or a plugin that throws on startup. For ASP.NET Core sites, compare the hosting bundle and runtime with the <a href=\"https:\/\/hostandtech.com\/kb\/plesk-windows\/deploy-aspnet-core-app-plesk-windows\/\">ASP.NET Core deployment guide<\/a>, and check the <code class=\"\" data-line=\"\">web.config<\/code> against <a href=\"https:\/\/hostandtech.com\/kb\/plesk-windows\/web-config-redirects-url-rewrite-plesk-windows\/\">web.config rules for Plesk<\/a>.<\/p>\n<p>To keep the site up while you fix the code, you can switch protection off for that pool only: in <strong>IIS Manager &gt; Application Pools &gt; example.com &gt; Advanced Settings<\/strong>, under <strong>Rapid-Fail Protection<\/strong>, set <strong>Enabled<\/strong> to <code class=\"\" data-line=\"\">False<\/code>.<\/p>\n<p><strong>Warning:<\/strong> with protection off, a crashing app restarts endlessly and can use a lot of CPU. Treat it as a short-term measure and turn it back on once the crash is fixed.<\/p>\n<h3>Fix 4: The application pool identity is invalid<\/h3>\n<p>The Event Viewer entry mentions the identity, an incorrect user name or password, or batch logon rights, and the Security log may show an audit failure for a user such as <code class=\"\" data-line=\"\">IWPD_1<\/code> with &#8220;Unknown user name or bad password&#8221;. Run <code class=\"\" data-line=\"\">plesk repair web example.com -y<\/code> first. If the message returns:<\/p>\n<ol>\n<li>Open <strong>Computer Management &gt; Local Users and Groups &gt; Users<\/strong>, right-click the site&#8217;s user and choose <strong>Set Password<\/strong>.<\/li>\n<li>In <strong>IIS Manager &gt; Application Pools<\/strong>, select the site&#8217;s pool and click <strong>Advanced Settings<\/strong>.<\/li>\n<li>Next to <strong>Identity<\/strong>, click the <strong>&#8230;<\/strong> button, choose <strong>Custom account<\/strong>, click <strong>Set<\/strong>, and enter that user name and the new password.<\/li>\n<li>Start the pool.<\/li>\n<\/ol>\n<p>If the error returns after a few days, check whether a password policy or scheduled job on the server is changing local user passwords.<\/p>\n<h2>Common Issues &amp; Troubleshooting<\/h2>\n<h3>Only the Plesk panel shows 503, not the websites<\/h3>\n<p><strong>Cause:<\/strong> Plesk&#8217;s own service (port 8443) has failed, which is a different problem from a website pool.<\/p>\n<p><strong>Fix:<\/strong> restart the Plesk services from the Services console and read the Plesk log. Our <a href=\"https:\/\/hostandtech.com\/kb\/plesk-windows\/how-to-access-plesk-on-windows-server\/\">Plesk on Windows access guide<\/a> lists the ports and first checks.<\/p>\n<h3>The pool is Started but visitors still get 503 under load<\/h3>\n<p><strong>Cause:<\/strong> the pool&#8217;s request queue is full. IIS answers 503 when the queue length (1000 by default) is exceeded.<\/p>\n<p><strong>Fix:<\/strong> find why requests are slow, since a bigger queue only hides that. Check CPU and memory, then the database. If the server is out of headroom, see <a href=\"https:\/\/hostandtech.com\/vps-ssd-servers\">VPS plans<\/a> for a larger Windows VPS or ask our <a href=\"https:\/\/hostandtech.com\/contact\/\">team<\/a> to look at the server.<\/p>\n<h3>It began right after Windows or Plesk updates<\/h3>\n<p><strong>Cause:<\/strong> a failed update can leave IIS modules or the .NET runtime in a half-installed state.<\/p>\n<p><strong>Fix:<\/strong> see <a href=\"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-update-failed-fix\/\">Plesk Windows update failed<\/a>, then repeat Fix 1.<\/p>\n<div class=\"ht-faq-section\">\n<h2>Frequently Asked Questions<\/h2>\n<div class=\"ht-faq-item\">\n<h3 class=\"ht-faq-question\">Why does my Plesk website show 503 Service Unavailable?<\/h3>\n<div class=\"ht-faq-answer\">\n<p>The website\u2019s IIS application pool has stopped, usually after repeated crashes or because the pool\u2019s Windows user has an invalid password. IIS then answers every request with 503, and the domain\u2019s error log stays empty.<\/p>\n<\/div>\n<\/div>\n<div class=\"ht-faq-item\">\n<h3 class=\"ht-faq-question\">How do I restart an application pool in Plesk?<\/h3>\n<div class=\"ht-faq-answer\">\n<p>Go to Websites &amp; Domains, open the domain, click Dedicated IIS Application Pool for Website, then choose Switch Off followed by Switch On. Over Remote Desktop you can run plesk repair web with the domain name and the -y option instead.<\/p>\n<\/div>\n<\/div>\n<div class=\"ht-faq-item\">\n<h3 class=\"ht-faq-question\">What is Rapid-Fail Protection in IIS?<\/h3>\n<div class=\"ht-faq-answer\">\n<p>It is an IIS safeguard that disables an application pool after repeated worker process crashes, by default 5 failures within 5 minutes. Turning it off keeps the site trying to restart, but it hides a real crash that still needs fixing.<\/p>\n<\/div>\n<\/div>\n<div class=\"ht-faq-item\">\n<h3 class=\"ht-faq-question\">Why does the 503 come back after I restart the pool?<\/h3>\n<div class=\"ht-faq-answer\">\n<p>Restarting only treats the symptom. Check the System log for WAS events and the Application log for Event IDs 1026 or 1000 to see whether the app is crashing or the identity is invalid, then apply the matching fix.<\/p>\n<\/div>\n<\/div>\n<div class=\"ht-faq-item\">\n<h3 class=\"ht-faq-question\">Is this the same as a 500 error?<\/h3>\n<div class=\"ht-faq-answer\">\n<p>No. A 500 means the site\u2019s code or configuration failed while the pool was running. A 503 means IIS had no running pool to hand the request to, so you diagnose the pool rather than the page.<\/p>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>A 503 on a Plesk for Windows site means its IIS application pool has stopped. Restart it in Plesk, read the System log entry for the real cause, then fix Rapid-Fail Protection or a broken pool identity.<\/p>\n","protected":false},"author":1,"featured_media":299,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[66],"tags":[85,62,248,194,87],"class_list":["post-309","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-plesk-windows","tag-iis","tag-plesk","tag-plesk-windows","tag-plesk-obsidian","tag-windows-hosting"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Plesk 503 Service Unavailable: Fix a Stopped IIS App Pool<\/title>\n<meta name=\"description\" content=\"Plesk for Windows site showing 503 Service Unavailable? Restart the IIS application pool, then read the Event Viewer entry to fix the real cause.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Plesk 503 Service Unavailable: Fix a Stopped IIS App Pool\" \/>\n<meta property=\"og:description\" content=\"Plesk for Windows site showing 503 Service Unavailable? Restart the IIS application pool, then read the Event Viewer entry to fix the real cause.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/\" \/>\n<meta property=\"og:site_name\" content=\"Host And Tech knowledge base\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/stshostandtech\" \/>\n<meta property=\"article:published_time\" content=\"2026-09-29T17:06:12+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/09\/plesk-windows-503-service-unavailable-application-pool.webp\" \/>\n\t<meta property=\"og:image:width\" content=\"1200\" \/>\n\t<meta property=\"og:image:height\" content=\"630\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/webp\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@stshostandtech\" \/>\n<meta name=\"twitter:site\" content=\"@stshostandtech\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"6 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/\"},\"author\":{\"name\":\"admin\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#\\\/schema\\\/person\\\/b6fa79c48ddaba71af32e395c5b017ee\"},\"headline\":\"Plesk Windows 503 Service Unavailable: Fix a Stopped Application Pool\",\"datePublished\":\"2026-09-29T17:06:12+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/\"},\"wordCount\":1168,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#organization\"},\"image\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/plesk-windows-503-service-unavailable-application-pool.webp\",\"keywords\":[\"IIS\",\"plesk\",\"Plesk Windows\",\"plesk-obsidian\",\"Windows hosting\"],\"articleSection\":[\"Plesk on Windows\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/\",\"url\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/\",\"name\":\"Plesk 503 Service Unavailable: Fix a Stopped IIS App Pool\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/plesk-windows-503-service-unavailable-application-pool.webp\",\"datePublished\":\"2026-09-29T17:06:12+00:00\",\"description\":\"Plesk for Windows site showing 503 Service Unavailable? Restart the IIS application pool, then read the Event Viewer entry to fix the real cause.\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/#primaryimage\",\"url\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/plesk-windows-503-service-unavailable-application-pool.webp\",\"contentUrl\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/plesk-windows-503-service-unavailable-application-pool.webp\",\"width\":1200,\"height\":630,\"caption\":\"Title card: Plesk 503 Service Unavailable, restart the IIS application pool\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/plesk-windows\\\/plesk-windows-503-service-unavailable-application-pool\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Plesk Windows 503 Service Unavailable: Fix a Stopped Application Pool\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#website\",\"url\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/\",\"name\":\"Host And Tech knowledge base\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#organization\",\"name\":\"Host And Tech knowledge base\",\"url\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/wp-content\\\/uploads\\\/2026\\\/05\\\/logo-dark.png\",\"contentUrl\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/wp-content\\\/uploads\\\/2026\\\/05\\\/logo-dark.png\",\"width\":1134,\"height\":395,\"caption\":\"Host And Tech knowledge base\"},\"image\":{\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.facebook.com\\\/stshostandtech\",\"https:\\\/\\\/x.com\\\/stshostandtech\"]},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/#\\\/schema\\\/person\\\/b6fa79c48ddaba71af32e395c5b017ee\",\"name\":\"admin\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/aa1edac8bbadb442e059a5b65ad45a3b2e3ce689202373b96e3e567517ae4b39?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/aa1edac8bbadb442e059a5b65ad45a3b2e3ce689202373b96e3e567517ae4b39?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/aa1edac8bbadb442e059a5b65ad45a3b2e3ce689202373b96e3e567517ae4b39?s=96&d=mm&r=g\",\"caption\":\"admin\"},\"sameAs\":[\"https:\\\/\\\/hostandtech.com\\\/kb\"],\"url\":\"https:\\\/\\\/hostandtech.com\\\/kb\\\/author\\\/admin_fjj7qydm\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Plesk 503 Service Unavailable: Fix a Stopped IIS App Pool","description":"Plesk for Windows site showing 503 Service Unavailable? Restart the IIS application pool, then read the Event Viewer entry to fix the real cause.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/","og_locale":"en_US","og_type":"article","og_title":"Plesk 503 Service Unavailable: Fix a Stopped IIS App Pool","og_description":"Plesk for Windows site showing 503 Service Unavailable? Restart the IIS application pool, then read the Event Viewer entry to fix the real cause.","og_url":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/","og_site_name":"Host And Tech knowledge base","article_publisher":"https:\/\/www.facebook.com\/stshostandtech","article_published_time":"2026-09-29T17:06:12+00:00","og_image":[{"width":1200,"height":630,"url":"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/09\/plesk-windows-503-service-unavailable-application-pool.webp","type":"image\/webp"}],"author":"admin","twitter_card":"summary_large_image","twitter_creator":"@stshostandtech","twitter_site":"@stshostandtech","twitter_misc":{"Written by":"admin","Est. reading time":"6 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/#article","isPartOf":{"@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/"},"author":{"name":"admin","@id":"https:\/\/hostandtech.com\/kb\/#\/schema\/person\/b6fa79c48ddaba71af32e395c5b017ee"},"headline":"Plesk Windows 503 Service Unavailable: Fix a Stopped Application Pool","datePublished":"2026-09-29T17:06:12+00:00","mainEntityOfPage":{"@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/"},"wordCount":1168,"commentCount":0,"publisher":{"@id":"https:\/\/hostandtech.com\/kb\/#organization"},"image":{"@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/#primaryimage"},"thumbnailUrl":"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/09\/plesk-windows-503-service-unavailable-application-pool.webp","keywords":["IIS","plesk","Plesk Windows","plesk-obsidian","Windows hosting"],"articleSection":["Plesk on Windows"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/","url":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/","name":"Plesk 503 Service Unavailable: Fix a Stopped IIS App Pool","isPartOf":{"@id":"https:\/\/hostandtech.com\/kb\/#website"},"primaryImageOfPage":{"@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/#primaryimage"},"image":{"@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/#primaryimage"},"thumbnailUrl":"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/09\/plesk-windows-503-service-unavailable-application-pool.webp","datePublished":"2026-09-29T17:06:12+00:00","description":"Plesk for Windows site showing 503 Service Unavailable? Restart the IIS application pool, then read the Event Viewer entry to fix the real cause.","breadcrumb":{"@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/#primaryimage","url":"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/09\/plesk-windows-503-service-unavailable-application-pool.webp","contentUrl":"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/09\/plesk-windows-503-service-unavailable-application-pool.webp","width":1200,"height":630,"caption":"Title card: Plesk 503 Service Unavailable, restart the IIS application pool"},{"@type":"BreadcrumbList","@id":"https:\/\/hostandtech.com\/kb\/plesk-windows\/plesk-windows-503-service-unavailable-application-pool\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/hostandtech.com\/kb\/"},{"@type":"ListItem","position":2,"name":"Plesk Windows 503 Service Unavailable: Fix a Stopped Application Pool"}]},{"@type":"WebSite","@id":"https:\/\/hostandtech.com\/kb\/#website","url":"https:\/\/hostandtech.com\/kb\/","name":"Host And Tech knowledge base","description":"","publisher":{"@id":"https:\/\/hostandtech.com\/kb\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/hostandtech.com\/kb\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/hostandtech.com\/kb\/#organization","name":"Host And Tech knowledge base","url":"https:\/\/hostandtech.com\/kb\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/hostandtech.com\/kb\/#\/schema\/logo\/image\/","url":"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/05\/logo-dark.png","contentUrl":"https:\/\/hostandtech.com\/kb\/wp-content\/uploads\/2026\/05\/logo-dark.png","width":1134,"height":395,"caption":"Host And Tech knowledge base"},"image":{"@id":"https:\/\/hostandtech.com\/kb\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.facebook.com\/stshostandtech","https:\/\/x.com\/stshostandtech"]},{"@type":"Person","@id":"https:\/\/hostandtech.com\/kb\/#\/schema\/person\/b6fa79c48ddaba71af32e395c5b017ee","name":"admin","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/aa1edac8bbadb442e059a5b65ad45a3b2e3ce689202373b96e3e567517ae4b39?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/aa1edac8bbadb442e059a5b65ad45a3b2e3ce689202373b96e3e567517ae4b39?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/aa1edac8bbadb442e059a5b65ad45a3b2e3ce689202373b96e3e567517ae4b39?s=96&d=mm&r=g","caption":"admin"},"sameAs":["https:\/\/hostandtech.com\/kb"],"url":"https:\/\/hostandtech.com\/kb\/author\/admin_fjj7qydm\/"}]}},"_links":{"self":[{"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/posts\/309","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/comments?post=309"}],"version-history":[{"count":1,"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/posts\/309\/revisions"}],"predecessor-version":[{"id":314,"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/posts\/309\/revisions\/314"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/media\/299"}],"wp:attachment":[{"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/media?parent=309"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/categories?post=309"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hostandtech.com\/kb\/wp-json\/wp\/v2\/tags?post=309"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}