I need to synchronize the authenticator app with my iPhone and MacBook. It is stuck in a loop

A loop between Microsoft Authenticator on iPhone and sign-in on MacBook is usually caused by one of these conditions:

1. Authenticator is locked Unlock Microsoft Authenticator on the iPhone first. If the app is locked, the approval or entry box might not appear.
2. Notifications are silent or disabled On the iPhone, make sure notifications are enabled for Microsoft Authenticator. Silent or disabled notifications can prevent the approval prompt from appearing.
3. App version is outdated Update Microsoft Authenticator to the latest version. Microsoft does not support app versions more than 12 months old.
4. Network issue Switch between Wi‑Fi and mobile data on the iPhone. Also make sure Airplane mode is off. If a VPN is enabled, disconnect it and test again.
5. Device date and time are incorrect Verify that the iPhone date and time settings are correct.
6. Battery optimization or notification settings are interfering In Authenticator, tap Settings and check:
   • App updates is turned on
   • Turn off battery optimization is selected
   • Notification Settings > Show notifications is turned on
7. If using passkey cross-device sign-in from MacBook to iPhone Follow this flow:
   • On the MacBook sign-in screen, choose Other ways to sign in or Sign-in options.
   • Select Face, fingerprint, PIN, or security key.
   • On supported Windows devices, a QR code appears for cross-device authentication.
   • On the iPhone, scan the QR code with the system Camera app, not the camera inside Authenticator.
   • Select Sign in with passkey.
   • Make sure Bluetooth and an internet connection are enabled on both devices.
8. If the account was moved to a new iPhone If the Authenticator setup did not restore correctly, on the old iPhone make sure:
   • iCloud Drive is enabled
   • iCloud Keychain is enabled
   • iCloud Backup is enabled
   • Authenticator is turned on in the Saved to iCloud list
   • Authenticator is version 6.8.33 or later
   • The app was opened at least once before switching phones
   Then on the new iPhone:
   • Uninstall and reinstall Microsoft Authenticator
   • Open the app again and check whether the backup appears
9. If the work or school account still cannot be used after reinstall or device change The MFA registration may no longer be valid. In that case, the account needs to be re-registered for MFA. For work or school accounts, this is typically done by the organization’s IT admin.

References:

• Troubleshoot problems with Microsoft Authenticator
• Authentication did not complete
• Microsoft Authenticator FAQs
• Sign in with a passkey in Microsoft Authenticator