I have it installed and it appears to be working, but for some reason I still am being asked to authenticate with my account that is stored within TeamCity. I have tried a couple of things:
1. I have configured to allow email match, so I created a user in Azure AD and one in TeamCity with the same email address. That didn't get me in.
2. I enabled it such that TeamCity will create a user account on first logon, and then I verified that my Azure AD account was allowed the app within Azure AD settings. When I logged in, I didn't get an account created in TeamCity and I didn't get in, either.