If you are using mod_rewrite & find out some problem, you may need to do some debugging with the log write somewhere. For CentOS system with cPanel together with Apache or LiteSpeed, you may enabled mod_rewrite Debug Log as below.

• Edit Apache configuration located in “/etc/httpd/conf/httpd.conf“
• Find the corresponding VirtualHost for your domain which you want to debug.
• Add “RewriteLogLevel 9” underneath “UseCanonicalName” as below and save.

<VirtualHost 100.100.100.100:80>
  ...
  ...
  UseCanonicalName Off
  RewriteLogLevel 9
  ...
  ...
</VirtualHost>

• Restart Apache or LiteSpeed
• The Debug Log will be written in “/usr/local/apache/logs/error_log” file.