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 me

Answer 1

Another possible reason:

When you delete all test information from TestFlight, make sure you delete it for every language. In the testinformation page, select every localised language and check if the form is empty.