iTunesConnect: cannot transfer app because of "You must turn off TestFlight beta testing for the app that you want to transfer"

Question

Below you can see that testing for external testers are turned off:

same for internal testing:

but when I transfer app, one of the criterias are not met:

Why?

Answer 1

I had the exact same issue, resolved by removing all Tester and Build from the TestFlight as discussed above also (!important) remove everything fields at the App Information - Test Information.