Site on Plesk is not available: ModSecurity: Response body too large

Leonid Gukhman

Updated March 25, 2024 06:49

Plesk for Linux kb: technical ABT: Group A

Applicable to:

Domain is not available with the following error shown:

CONFIG_TEXT: 500
Internal Server Error
The following messages can be found in Domains > example.com > Logs or in /var/www/vhosts/example.com/logs/error.log file:

CONFIG_TEXT: [error] [client 203.0.113.2] ModSecurity: Output filter: Response body too large (over limit of 524288, total not specified). [hostname "www.example.com"] [uri "/index.php"] [unique_id "W*****U43-wA*****G"]

Domain exceeded the default SecResponseBodyLimit parameter for ModSecurity (512 Kb).

For domain

Log in to Plesk.
Navigate to Domains > example.com > Apache & nginx Settings
Add the following line to Additional directives for HTTP and to Additional directives for HTTPS:

CONFIG_TEXT: <IfModule mod_security2.c>
SecResponseBodyLimit 536870912
</IfModule>
Press Apply .

Server-wide

Log in to Plesk.
Navigate to Tools & settings > Web Application Firewall (ModSecurity) > Settings > Custom directives section:
Add the following line:

CONFIG_TEXT: SecResponseBodyLimit 536870912
Press Apply

Additionall steps for Ubuntu 18.04/20.04
1. open /etc/apache2/plesk.conf.d/server.conf
2. modify SecResponseBodyLimit value
3. restart apache