IE 8/9/10/11 Gives "Unsupported Browser" Error

PROBLEM

When I use IE/Internet Explorer 8/9/10/11 to access my atmail email account, I get an unsupported browser error. The login page states that IE8+ is supported.

ENVIRONMENT

• On-Premise Server + WebMail Installations: Version 7.0 > Current Version
• Webmail Only Installations: Version 7.0 > Current Version

CAUSE

Internet Explorer compatibility mode is enabled. When Internet Explorer is in compatibility mode, it mimics Internet Explorer 6. This is why you see this error as only Internet Explorer 8+ is supported.

RESOLUTION

Ensure that compatibility is not enabled when accessing an atmail account via the WebMail UI.