Administrator access to Teams lost

Hello, I created a new team for a validation with my private email address. That worked out pretty well. After problems with my company account I have deleted all entries in the Android App Microsoft Authenticator. If I add my private account to the Authenticator by password, I will also be displayed privately. I have an 8 digit code. My business accounts have a 6-digit code. If I want to log in to my self-created Teams, the user is checked first. I can confirm this successfully with the Authenticator.On the next page I choose the tenant. And teams send me a request for the Authenticator. On my mobile phone I get the message: "Notifications from your business, school or university account cannot be processed ...". If I want to login with code I can only enter 6 digits of my 8 digit code. I can't find a QR Code that I can scan with the Authenticator. Deactivating the Authenticator in my private account will not change anything for teams. I use teams on Ubuntu, Windows and have tried the web client.

I have 2 contacts to Microsoft Support Chat and threads in 2 Forums. It's the 10th day without access.

https://answers.microsoft.com/de-de/msoffice/forum/all/als-administrator-in-teams-ausgesperrt/eea74107-c4d9-4f23-aa7b-cb2bde40d3eb
https://docs.microsoft.com/answers/questions/24623/administrator-access-to-teams-lost.html