If you are unable to login into Webmail , and you are getting an Error: “Your Internet Address has changed since the beginning of your Mail session. To protect your security, you must login again.”
To fix this problem, you may do the following:
1)You can turn off ‘checkip’ feature in Horde server-wide.
2)Edit the /usr/share/psa-horde/config/
$conf[‘auth’][‘checkip’] = true;
$conf[‘auth’][‘checkip’] = false;
Please note that this modification cannot be configured per user basis and will affect all the webmail users in the server.