Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Based on your description, it appears that you are using a work or school account (for example, ******@yourorganization.com).
To better understand the issue, could you please provide the following information?
-When you say your access is blocked, what is the exact error message you receive?
-Do you have any other available sign-in or verification methods?
-Do you see the iPad listed on the Security Info page (https://mysignins.microsoft.com/security-info)?
If you can still access the Security info page, please remove the iPad from your registered authentication methods and register Microsoft Authenticator again on your iPhone.
For guidance, please refer to How to add your accounts to Microsoft Authenticator | Microsoft Support
If you cannot access your account because you are unable to complete authentication and have no alternative sign-in methods available, please contact your IT administrator and ask them to reset your MFA registration. After the reset, you can register Microsoft Authenticator again on your iPhone.
For reference, your administrator can follow the steps in this article: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID |…
If you are unsure who your administrator is, please refer to How do I find my Microsoft 365 admin? | Microsoft Support
I hope this information helps.