TPS included a file called “Profile Data” in your TPS game folder (along with your save files, DLC items, update, compatibility pack, etc.) It contains a bunch of information including your BAR stats, heads and skins, and other stuff.
I’m speculating that if that got deleted, it might have also caused an issue with the link between your SHiFT account and your XBox Live gamer tag. That’s why I asked if that file was still intact. You can check for your self by going to System > Storage > main drive > Games & Apps > TPS, where “main drive” is the place you have your saves stored (eg internal drive, memory unit, cloud save).
I’ve seen a couple of reports of people having issues with their SHiFT account being inaccessible, but no-one that I remember has posted a definitive reason/fix. You could try logging in to your SHiFT account via the SHiFT web site: you could de-link and then re-link your GT to see if that resolved the problem.
However, I’m not sure if this is a good idea if you no longer have a current Gold subscription (I’ve had Gold before creating a SHiFT account, and never let it lapse, so I don’t know if there’s any difference in procedure for linking accounts without Gold.)
That’s why I suggested filing a support ticket. FYI they seem to be responding in 24-48 hours at the moment.
I’m also assuming that you’re getting updates and hotfixes ok, so it’s not simply a case of your internet connection being flaky. Note that the SHIFT login attempt happens when you start the game up; I have had the situation where the attempt timed out, but hitting “B” to go back to the splash screen, then hitting “Start” again seemed to fix that. (You could also try that to see if it works in the mean time.)
Hope you get a response soon and get things working again. Please keep the thread updated with anything you learn; as I said above, I’ve seen similar reports before but not the conclusion, so it’s possible that someone else may come looking for an answer to the same problem later.