413 Request Entity Too Large in Plesk: How to Raise the Upload Limit (nginx, Apache and PHP)

Overview

“413 Request Entity Too Large” in Plesk means the upload was bigger than nginx is allowed to accept, so it was refused before PHP or your application ever saw it. Fix it in two places for the domain: raise client_max_body_size under Apache & nginx Settings > Additional nginx directives, then raise upload_max_filesize and post_max_size in the domain’s PHP Settings. If the 413 page doesn’t say nginx, ModSecurity or a CDN is the one blocking it.

This guide is for Plesk Obsidian on Linux, on a VPS or dedicated server, where an upload of a large image, video, plugin, theme or database dump fails. Every request passes through up to four gates, each with its own size limit, and raising only one of them is why so many fixes “don’t work”. You’ll find which gate stopped the upload, raise it, and test the result with a real file instead of guessing.

Prerequisites

• Plesk administrator access, or a customer account with permission to change PHP and web server settings.
• SSH root access for the testing and log steps (optional but much faster).
• The size you need. Pick a value a little above your largest real upload, such as 256 MB for site backups. Setting everything to unlimited makes it easy for anyone to fill your disk.

Step 1: Find out which gate refused the upload

Look at the error page and the logs before changing anything.

Over SSH, the domain’s logs tell you directly. Replace example.com with your domain:

grep -i "too large body" /var/www/vhosts/system/example.com/logs/proxy_error_log | tail -5
grep -i "ModSecurity" /var/www/vhosts/system/example.com/logs/error_log | tail -5

A line containing client intended to send too large body: 104857600 bytes is nginx, and it tells you the exact size of the failed upload. These logs are also in Plesk under Websites & Domains > example.com > Logs.

Step 2: Raise the nginx limit for the domain

1. Go to Websites & Domains and open the domain.
2. Click Apache & nginx Settings (on the Hosting & DNS tab in recent Plesk versions).
3. Scroll to Additional nginx directives and add the line below.
4. Click OK. Plesk tests the configuration and reloads nginx.

client_max_body_size 256m;

If Plesk refuses with "client_max_body_size" directive is duplicate, the value is already being written for this domain from another setting. See the troubleshooting section below.

To confirm what nginx is really using after the change:

nginx -T 2>/dev/null | grep -n client_max_body_size

Step 3: Raise the PHP limits

nginx now lets the upload through, but PHP has its own ceiling. Open the domain’s PHP Settings (in recent Plesk versions it’s on the domain’s Dashboard or Dev Tools tab, or click the PHP version shown for the domain) and set:

Pick Custom for any value not in the drop-down, then click OK. If the domain’s PHP handler runs under a service plan with locked settings, change the plan instead (Service Plans > plan > PHP Settings) so the change isn’t reverted on the next sync. For more on handlers and versions, see managing PHP versions in Plesk.

To check the values PHP actually loaded, create a temporary file in the site’s document root:

<?php phpinfo();

Save it as info-7f3k.php, open it in a browser and search for upload_max_filesize and post_max_size. Delete it straight afterwards; it shows a lot about your server.

Step 4: Apache and ModSecurity (only if they blocked it)

Apache 2.4.53 and later already allow request bodies up to 1 GB by default, so Apache itself is rarely the limit unless someone set LimitRequestBody lower. ModSecurity is the usual suspect. Its default request body limit is about 12.5 MB, and when it blocks you’ll see a log line mentioning Request body (Content-Length) is larger than the configured limit.

Raise it for one domain under Apache & nginx Settings > Additional Apache directives, in both the HTTP and HTTPS boxes:

<IfModule mod_security2.c>
    SecRequestBodyLimit 268435456
</IfModule>
LimitRequestBody 268435456

268435456 bytes is 256 MB. Don’t switch ModSecurity off for the whole site to get one upload through; you lose its protection for every other request.

Step 5: Test with a real file

Rather than clicking upload and waiting, send a test request of a known size from the server or your own computer:

fallocate -l 200M /tmp/upload-test.bin
curl -s -o /dev/null -w '%{http_code}' -F "file=@/tmp/upload-test.bin" https://example.com/ ; echo
rm /tmp/upload-test.bin

A 413 means a gate is still too small. Any other code, including 200, 403 or 405, means the body got through nginx; your application simply didn’t expect a file at that URL. Finish with a real upload in your application.

Troubleshooting

Invalid nginx configuration: “client_max_body_size” directive is duplicate

Plesk already writes a client_max_body_size line for this domain, so adding a second one in the same block fails the config test. Find where it comes from:

grep -rn client_max_body_size /var/www/vhosts/system/example.com/conf/ /etc/nginx/conf.d/ /etc/nginx/plesk.conf.d/ 2>/dev/null

If the existing value comes from a field on the Apache & nginx Settings page, change it there instead of adding a directive. If it’s in a custom file under /etc/nginx/conf.d/ from an earlier fix, edit that file, then run nginx -t and systemctl reload nginx.

The change saved but uploads still fail with 413

Check the page footer again: if it’s not nginx any more, a different gate is now the smallest. Also make sure you edited the right site. Subdomains and aliases served as separate domains in Plesk have their own settings. If the site sits behind Cloudflare, uploads larger than 100 MB are refused on the Free and Pro plans no matter what your server allows; upload through a DNS-only (grey cloud) hostname or the server’s IP instead.

WordPress: The uploaded file exceeds the upload_max_filesize directive in php.ini

nginx is fine; PHP is the limit. Repeat Step 3 and confirm with phpinfo(). On a WordPress multisite, also raise Max upload file size under Network Admin > Settings, which WordPress enforces on its own.

504 Gateway Timeout or the upload stops partway through

The size limit is fine, but the upload takes longer than a timeout. Raise max_input_time and max_execution_time in PHP, and for very large or slow uploads add client_body_timeout 300s; next to client_max_body_size in the nginx directives. If nginx itself won’t restart after an edit, follow fixing nginx failed to start in Plesk.

Running Plesk yourself on a Host & Tech VPS gives you root access for every step here. If you’re setting up a new site, creating a website in Plesk covers the rest of the hosting settings, and on cPanel servers the same PHP limits live in WHM’s PHP configuration.