The system is unavailable now so you have been signed out of Microsoft Lync.
Other symptoms of the issue is that it will log you in, but your contacts list isn’t populated and you can’t send or receive messages
The fix for this error is really simple and Microsoft has this documented in the following KB. Follow my screen shots below to update to the latest version of Lync for Mac 2011
Click Check for Updates
Update will Download
Enter Admin Password – If prompted
Thanks for visiting and reading my posts. I am always looking for more ideas. Please comment or email me with what you would like to see.
Kelsey Epps Office365 MVP