CloudFlare modifies your DNS to point to their servers so because of this you cannot access cPanel using yourdomain.com/cpanel or yourdomain.com:2082 and the same for Webmail and WHM.
Instead you will need to use the URL http://cpanel.yourdomain.com
This also applies for:
http://webmail.yourdomain.com
http://whm.yourdomain.com
http://cpanel.yourdomain.com
