When I open my existing solution in Visual Studio 2012 professional, I got the above error. This used to work but something messed up after the computer is rebuilt.
I have installed Visual Studio 2015 Community and can connect to the same collection correctly.
I also tried to use a browser to connect to the same collection. It works fine also.
Cleaning all files in AppData\Local\Microsoft\Team Foundation\4.0\Cache does not work.
It should not be a firewall or proxy issue since Visual Studio 2015 works.
Anyone knows what is wrong with Visual Studio 2012 and how to fix it?
Edit:
This error can happen with later versions of TFS:
Team Foundation Error
TF400324: Team Foundation services are not available from server TFSServer\DefaultCollection.
Technical information (for administrator):
Unable to connect to the remote server
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond xxx.xxx.xxx.xxx:443