Dear @riqwertz,
Thank you for posting your question in the Microsoft Q&A forum.
I apologize for any inconvenience you may encounter when using our services/ products. Based on your description, kindly try these following steps:
Please sign in to Microsoft account | Sign In or Create Your Account Today – Microsoft and open the Security section. From there, update or add a backup (recovery) email address and confirm whether the change can be saved successfully.
When you sign in to Minecraft, the verification code is being sent to a recovery email address that you do not recognize. If a verification code is delivered to an address you did not request or recognize, it can indicate that someone compromise the account.
I sincerely hope you understand that the initial steps I suggested may not have completely fixed the issue, as there may still be underlying causes that have not yet been identified. I am here to work closely with you, troubleshoot effectively, and explore every possible solution to ensure the best possible outcome.
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