New employee cannot receive MFA code when signing in to Outlook

For a first-time work or school account sign-in where Microsoft Authenticator is installed but no code or notification arrives, use this sequence:

1. Try the sign-in again, but avoid repeated attempts. Microsoft may temporarily stop sending codes after many repeated requests or unusual activity. If there were multiple attempts already, wait and try again later, or choose a different MFA method if one is available.
2. On the sign-in page, select Sign in another way or a different verification method. If another method was set up, such as SMS, phone call, office phone, or email, use that method to complete sign-in.
3. If SMS or phone call is available, request it carefully. For phone call or text delivery, attempt up to five times in 5 minutes. Do not make excessive or repetitive requests beyond that, because that can cause temporary blocking.
4. Check whether the verification is going to a different device. If Microsoft Authenticator was previously active on an older phone, the push notification may be sent there instead of the current phone. If the old phone is still available, open Authenticator on that device and check for the approval prompt.
5. Check for common delivery blockers.
   • If the phone blocks texts from unknown numbers, change that setting and request the code again.
   • If a third-party security app is installed on the phone, disable its protection temporarily and request another verification.
   • If using a VOIP number, replace it with a mobile phone number, because VOIP numbers cannot be used for verification codes.
6. Verify the registered security information. Sign in to the Security info page using any method that still works, then select Update info and confirm the phone number or other sign-in methods are correct. If none of the listed methods work, choose I don't have any of these if that option is shown.
7. If this is a new phone, remove the old phone entry and add the new one. On the Additional security verification or Security info page, delete the old phone or outdated method, then add the new phone and re-register Microsoft Authenticator.
8. If no alternative method works, contact the organization’s IT help desk. For work or school accounts, the help desk or administrator can clear or reset MFA settings so registration can be completed again. If a mobile device was lost, replaced, or the setup is stuck, this is the supported next step.

If the issue is specifically that text messages are unreliable, Microsoft recommends using the Microsoft Authenticator app or phone call method instead, because Authenticator can receive notifications over cellular or Wi-Fi and can generate codes even without mobile signal.

References:

• Frequently asked questions about Microsoft Entra multifactor authentication
• Use a screen reader to set up and troubleshoot multifactor authentication
• Common problems with two-step verification for a work or school account
• Microsoft Authenticator FAQs