I tried a number of things before I stumbled across the solution.

Off to StackOverflow I went and it seems, this is quite a common problem.

I tried all the usual suspects like restarting Visual Studio and re-starting Windows. Have you Tried Turning it On and Off Again? I knew my credentials and permissions were correctly set but tried numerous times anyway. I went to connect to this via my VS IDE but got the TF31003 error dialogue box. Recently though, I needed to connect to a Visual Studio Online account that I’d setup under a different Microsoft account. Connecting to a different Team Foundation Service I hooked up my Visual Studio IDE with my Team Foundation Service account and it just worked. As an agile practitioner, the ability to hook up to an infrastructure capable of handling agile goodness like automated testing, continuous integration, continuous delivery, automated builds etc, is to good to pass up. I’ve used Visual Studio 2012 Ultimate and Team Foundation Service (the online version of TFS, hosted in the cloud) successfully for some time. Using Team Foundation Service TF31003 Error Dialogue Box Here are a couple of possible solutions to the error. If you have more than one Microsoft account as well, you just increased your chances greatly. If you use Visual Studio Online or Team Foundation Service, and the Visual Studio IDE, it’s possible you’ll come across the TF31003 error.

Visual studio 2012 ultimate