1. Firstly, access to Smartermail. Example: mail.domain.com
2. Kindly click on the "Tools" from Menu Bar. Select "Compatibility View Settings".
3. Add your domain name or IP.
4. Once add your domain name, click "Close". Try to login to Smartermail. It should not be any problem to login now.
5. Have a try.
*Note: This is not compatible with IE 11 in Windows 8.