Keith Abluton blogged about an issue with Outlook for Mac 2011 using WAP in Windows Server 2012 R2.
Scenario: You are publishing your Microsoft Exchange services (OWA, ActiveSync, Outlook Anywhere) through Web Application Proxy in Windows Server 2012 R2. Using a web browser for OWA works as expected but clients using Outlook for Mac 2011 cannot get their mail. The error you receive on the Outlook for Mac client is “bad username or password.” There may be other clients not working correctly as well including, but no limited to, Android phones using ActiveSync.
Cause: Outlook for Mac is a “non-SNI capable” client. Web Application Proxy utilizes the Server Name Indication (SNI) feature of SSL TLS and clients that do not support this will not work correctly. The quickest and easiest way to tell if your client is non-SNI capable is to get a network trace of the SSL traffic that the client is sending. If getting it from the client is not possible you can also get a network trace from the WAP server.
Read more at source: http://blogs.technet.com/b/keithab/archive/2014/07/24/outlook-for-mac-2011-not-working-through-web-application-proxy.aspx