When I try to communicate with the remote repo (fetch, push, pull), I just get this exception:
TF400813: Resource not available for anonymous access. Client authentication required.
I can do the same using GitExt or git bash without problems, so it seems like it's just VS that lost some setting. I can't find anywhere to "re-authenticate" or similar, though. I do have basic credentials set up, and am signed in with the same live id in Visual Studio.
Visual Studio uses Live ID to talk to visualstudio.com and shares the credentials with Internet Explorer for a single signon experience. It's likely that your browser has some Live ID cookies (which is why you're not prompted), but not for the credentials you actually want to authenticate with (which is why you get permission denied).
Can you close Visual Studio, open Internet Explorer and explicitly log out of your Microsoft Account?
When you restart Visual Studio, you should then be prompted for credentials when you connect to Visual Studio Online.
I had same problem and solution by Edward Thompson didn't helped me. However I found another one - in Visual Studio open:
Help / About Microsoft Visual Studio / License status (link in upper right corner)
There in new window in section All Accounts I had a message at my Microsft Account that I need to reenter credentials. When I did it, I was able again to connect to Git repositories in Visual Studio Online.
