In a shared hosting environment, the size of .htaccess files is limited to 512 KiB to ensure proper functioning of the Apache web server.
If the .htaccess file size exceeds 512 KiB, the site will display a 403 Forbidden error and the corresponding error can be seen in the Apache error log as follows:
[2023-05-09 08:10:48.893481] [vhost: example.com] [directive:error] [pid: 3 9881] [client: 188.8.131.52:0] configuration file too big (548900 bytes): /data01/virt123/domeenid/www.example.com/htdocs/.htaccess
Usually the .htaccess file gets larger due to some plugins, used in your application, which automatically add lines (e.g. IP blockers). Therefore, if such an error occurs, it is necessary to check the operation of such a plugin and remove unnecessary .htaccess lines so that the file size does not exceed 512 KiB.