Why Authenticator wont let me enter security number when prompted.

If you are experiencing issues with the Microsoft Authenticator app not allowing you to enter the security number when prompted, it could be due to a few reasons:

1. Same-Device Number Matching: If you are trying to sign in on the same device where the Authenticator app is installed, you may receive a prompt to approve the sign-in directly in the app instead of entering the number. This feature is designed to enhance user experience by allowing a simple Yes/No response instead of requiring you to type the number.
2. App Configuration: Ensure that you are using the latest version of the Microsoft Authenticator app. Sometimes, updating the app can resolve unexpected behavior.
3. Legacy Clients: If your organization uses legacy clients that do not support modern authentication, you may need to set up app passwords instead of using the regular password. This requires clearing your sign-in information and using the app password for authentication.
4. Device Settings: Check your device settings to ensure that the Authenticator app is allowed to run in the background and is not restricted by battery optimization settings, which can prevent it from functioning properly.

If the issue persists, consider reaching out to your IT department for further assistance, as they may have specific configurations or requirements for linking your work email to the Authenticator app.

References:

• How number matching works in MFA push notifications for Authenticator - Authentication methods policy
• Frequently asked questions about Microsoft Entra multifactor authentication