Fix a website's Internal Server Error

After transfer a website into a new server, we are having an Internal Server Error on a website: -----ERROR:----- Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator at xxxxxxx@[login to view URL] to inform them of the time this error occurred, and the actions you performed just before this error. More information about this error may be available in the server error log. Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request. ----------------------------- The site was developer in CodeIgniter. I think (but I'm not sure), it has something to do with the .htaccess file. When we remove this first block from the .htaccess file, the Internal Server Error disappears, but then we get an 404 not found error: -----CODE:----- <IfModule mod_rewrite.c> Options +FollowSymLinks RewriteEngine on # Send request via [login to view URL] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.*)$ [login to view URL]$1 [L] SetEnv CI_ENV production </IfModule> ----------------------------- I will provide cPanel access