Mac Lync 2011 will not connect to my Office 365 account

Question

With valid credentials that work on a Windows Lync client, I am able to log in, but not using Mac Lync 2011. The error I get is that credentials are invalid.

Answer 1

This hotfix from Microsoft fixes the problem

http://www.microsoft.com/en-us/download/details.aspx?id=36517

Answer 2

Make sure that your Lync 2011 configuration settings are manually set to the following :

Internal server name : sipdir.online.lync.com:443
External server name : sipdir.online.lync.com:443

You can refer to the following guide Lync 2011 troubleshooting