He sees the login screen, upon logging in it redirects him to the same screen with error saying:
IP address has changed
Upon testing it on my computer, I wasn’t able to find the error.
Reason for IP address has changed – cPanel webmail error
The reason for IP address has changed error in cpanel 11 was using a proxy server. He was using cable net which was utilizing proxy, causing cpanel to log him out with error that ip address is different.
How to solve IP address has changed – cPanel webmail error
This error can be resolved by:
1. Using subdomain path (webmail.domain.com or cpanel.domain.com)
2. Using email clients (outlook express, thunderbird, etc)
3. Using a normal internet connection if possible
4. Making changes to cPanel settings to allow such connections (cPanel Cookie IP validation settings). Changing cookie ip validation settings to “loose” will diminish the frequency of re-authentication thus preventing the error.