Problem solved: I deleted and reinstalled the Migros app and was finally able to register the Visa debit card...at the same time, of course, I had to re-register the other previously registered cards (Mastercard, Twint). On 17.04.2023 I received a message from my Migros Bank telling me that the Migros app could no longer be linked to the Migros bank account and that from 15.05.2023 I would have to register my Visa debit card in the Migros app. After several attempts, I can't register this card, nor can I delete an old card that has been registered but is no longer valid. Nor can I register my Mastercard as a means of payment. In my opinion, this is a problem with the Migros app.