Your Internet Address has changed since the beginning of your Mail session. To protect your security, you must login again.
This error most probably appear when you using proxy server or multiple IP for your Internet Access.
To overcome this issue, you need to turn off the checkip value from your horde configuration.
1. Open file locate at /usr/local/cpanel/base/horde/config/conf.php.
2. Change the value from,
$conf[‘auth’][‘checkip’] = true;
$conf[‘auth’][‘checkip’] = false;
3. Restart the email services.