Hello,
I enabled the experimental co-authoring flag in PowerApps.
I created a PAT with just about every permission that could be relevant.
I created a new folder in a repository I have access to. It required me to do an initial commit in the folder so I created a blank README file.
In PowerApps, I went to the settings, connect to Git source control by specifying the repo, branch, and the folder name.
I was challenged for my credentials.
I clicked "Sign in", and I was sent back to this screen with no indication there was an error.
I changed the folder name to one that did not exist, and THEN it started to work.
Desired resolution: Provide a useful error message back to the user.