Hello Ville L123123
Thank you for posting to the Microsoft Community.
I understand that you've lost access to your account due to 2FA. May I please verify the type of account you are using? Is it an M365 work/school account or a Microsoft/personal account like Hotmail/outlook.com?
In the meantime, since you posted in the business category and if you are using a business account. It seems you authentication method is corrupted and needs to be reset by you administrator, however before involving the admin, could you please.
First try to Clear App Cache and Data:
- On your iPhone, go to Settings > General > iPhone Storage.
- Find the Microsoft Authenticator app and select it.
- Tap Offload App to clear the app's cache and data
Secondly, Use a Different Sign-In Method:
- If possible, try using an alternative sign-in method like a text message or email verification
If the above still does not fix the authentication issue, then its best to reset the authentication method
Only the admin can reset the authentication by accessing the Azure admin portal. In the Entra portal, the administrator can set your account to **Require new MFA registration.**This disables all previous authentication methods, and you will then be prompted to configure a new MFA authentication method the next time you sign in.
The admin can use below link to reset for you the MFA to How do I find my Microsoft 365 admin? - Microsoft Support
If you need guidance on how to find your admin, please refer to How do I find my Microsoft 365 admin? - Microsoft Support
If your account is Microsoft personal account (outlook.com/live.com/Hotmail.com), please reply back to us, so we can involve personal account team for further assistance.
Thank you for your kind understanding and have a great day.