A new feature of Visual Studio 2013 is the ability to sign in with a Microsoft Account and have your settings be persisted across all of your instances of Visual Studio, amo
If the Command prompt don't work for you, try logging in with your account that is working then log out and then try again with your other account.
I was also able to fix this by signing in putting my product key in and then signing out and then logging in under my new login.
There is a comment about this under this answer, but I think it's important to list it here. If you want to preserve your settings, export them first because they will be lost.
From MSDN forums - since I had to hunt around far too much to find the solution to this:
Worked for me.
I faced this issue Many time from different scenarios
one of them when I tryed Connecting to team foundation server for different Logged User
so the solution is easy Just Click Switch User
hope this help you