If ModSecurity is enabled and want to disable it server-wide, follow the steps:
Find the ID from the domain error log. The error log will be in the format:
-------
Message: Access denied with code 403 (phase 2). Pattern match "xxxx" at REQUEST_HEADERS:User-Agent. [file "xx_asl_useragents.conf"] [line "xxx"] [id "330039"]
-------
Here '330039' is the ID.
If all the domain documet root is under '/var/www/vhosts', add the following configuration under the apache configuration file:
If the server is plesk
------
<IfModule security2_module>
<Directory /var/www/vhosts>
SecRuleRemoveById 330039
</Directory>
</IfModule>
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Now, check if nginx config is correct using the command :
#httpd -t
#/etc/init.d/httpd graceful