I have been getting this message every time I logon to my Gmail. Other users on the web have also been getting the same message.
Took me a while, but drawing from what others have said, I took a hard look at Googles new fangled "Hangouts. YES ! That was the problem - Google has got a hangup about their Hangouts. Nothing to do with your computer, it is Google.
So get rid of the Google Hangouts until Google sort out their problems.
Turn off Hangouts and start using the old Chat.
Edited by John Bull, 20 June 2014 - 02:18 PM.