Here is how to disable mod_sec for a single domain name in cPanel.
To disable mod_security COMPLETELY, add the following line to the .htaccess file
To only disable HTTP POST scanning, use the following instead:
On a not-cPanel configuration you can add the following to Apache’s virtual host file (/usr/local/apache/conf/httpd.conf):
<IfModule mod_security2.c> SecRuleEngine off </IfModule>
If you want to disable mod_sec for a single file/folder instead, you can follow this guide here.