Nasty one. I was logged in to Visual Studio 2015 with one of my several credentials I can login to Visual Studio, and I get the error message TFS30063: You are not authorized to access (site name here).
Nothing new about that error – I did what I usually do and logged out in Visual Studio and logged in again. No help. Delete all other profiles in Visual Studio and log in again. No help. Log on with my default browser to visualstudio.com using the account that is supposed to have access to the source code repository. No help. Restart Visual studio. No help. Log out to every browser on my computer (Chrome, Firefox, Firefox developer edition, Edge) and restart Visual Studio. Get latest => It works 🙂