I had the same issue today, both on Xcode and on Transported, but it worked after I restarted the computer. It probably deleted the cached files when I did it, so doing the steps suggested above might also work.

This also happened to me on App Store Connect. First upload of the app. Didn't get any e-mails

This also affects me. I'm trying to test a game in an adults school and they don't know what to do with the invitation.