Microsoft has introduced an extra layer of security to its Authenticator app on iPhone, which ACU uses for Multi-Factor Authentication. This extra steps requires users to re-enter their fingerprint, passcode or face ID when opening the app to approve an MFA prompt. This is called iPhone App Lock and is enabled by default.

To disable the iPhone App Lock feature:

1. Open the Microsoft Authenticator app.

2. Use your passcode, fingerprint, or face ID to unlock the app.

3. Tap the three lines in the top left hand of the Authenticator app to open the menu then tap Settings.

4. Tap the green slider next to App Lock to disable App Lock on your device.