In a shared hosting environment limiting the .htaccess file size to 512KiB ensures proper functioning of the Apache web server.
If the .htaccess file size exceeds 512 KiB, the site will display a 403 Forbidden error. The corresponding error can be seen in the Apache error log as follows:
Usually the .htaccess file gets larger due to some plugins, used in your application, which automatically add lines (eg IP blockers). Therefore, if such an error occurs, it is necessary to check the operation of such a plugin. Then remove unnecessary .htaccess lines so that the file size does not exceed 512 KiB.
Read also “Examples of .htaccess rewrite rules“.