I have VS2012 and VS2010 on the same machine. VS2012 is connected to Team Foundation Server (now VSOL/Visual Studio Online) but, VS2010 gives below error when trying to add Team Foundation Server (now Visual Studio Online) to the list.
TF31002: Unable to connect to this Team Foundation Server Possible reasons for failure include:
-The name, port number or protocol for TFS is incorrect.
-The team foundation server is offline.
-Password has expired or is incorrect.
For further information, contact Team Foundation Server administrator.