MFA account verification error

Question

There is an error when an SMS is sent for identification. Since I cannot logon, I cannot see/change any setting.

Answer 1

Because sign-in fails at the SMS step and settings cannot be accessed, the issue must be handled by an administrator or Microsoft support, depending on the role in the tenant.

First, validate that the problem is not a simple delivery or input issue:

1. Make sure the phone can receive calls/SMS and has service.
2. Confirm the correct phone number and country/region code are configured for the account in security verification settings (an admin can check this in Microsoft Entra ID).
3. When SMS is received, ensure the exact verification code is entered. If using phone call, respond by pressing the pound key (#) as required.

Relevant causes and basic fixes from Microsoft Entra MFA behavior:

• If the error is “We didn’t receive a response. Please try again.”, it can be caused by:
  • Phone call not answered.
  • Provider unable to send call/SMS.
  • Time-out due to no response.
  • Incorrect phone number in security verification settings. In these cases, verify phone service and number, and try another verification option if available.
• If the error is “Sorry, our account verification system is having trouble…”, this occurs when the response contains invalid input (for example, wrong code or incorrect phone response). Ensure the correct code is used or the correct key is pressed on the call.

If sign-in is blocked after multiple attempts:

• Microsoft Entra multifactor authentication may temporarily block further attempts when unusual activity or repeated sign-in failures are detected. In that case:
  • Wait before trying again, or
  • Use a different MFA method if one is already configured (such as Microsoft Authenticator app, alternate phone, or email, depending on tenant policy).
  • If malicious activity is suspected, an IT administrator should review Microsoft Entra sign-in logs.

If no alternative MFA method is available and access is completely blocked:

• If there are other Global Admins in the tenant:
  • Another admin can reset or reconfigure MFA for the affected user, or require re-registration of MFA methods so the user can set up a working method again.
• If the locked-out user is the only administrator:
  • The Microsoft Data Protection team must be involved. Use the regional customer service phone numbers to open a support ticket and work through identity verification so MFA can be reset and access restored.

If SMS itself is unreliable or failing repeatedly:

• Consider switching users from SMS to more reliable methods such as the Microsoft Authenticator app or phone call. For MFA Server environments, two-way SMS is deprecated and should be replaced with the mobile app or phone call; one-way SMS is supported only in limited scenarios.

In summary, resolution typically requires either:

• Correcting phone/SMS issues and input, or
• Using an alternate verification method, or
• Having an administrator reset MFA / require re-registration, or
• In single-admin lockout scenarios, contacting Microsoft support (Data Protection team) via the official support channels to regain access.

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References:

• "We didn't receive a response" error message when you try to sign in by using Azure Multi-Factor Authentication
• "Account verification system is having trouble" error message when you try to sign in by using a work or school account
• Common problems with two-step verification for a work or school account
• Troubleshoot Microsoft verification code issues
• Two-way SMS unsupported
• Error Code: 399287 - Microsoft Q&A Unable to Verify Identity for Azure Login – Error 399287
• MFA admin account no longer works - Microsoft Q&A
• I have a Micrsoft business account and I am the admin and the only user registered under this account. I can't log in because i have replaced my phone and the authenticator doesn't work. - Microsoft Q&A
• I need to reset my mfa methods - Microsoft Q&A
• Having problems getting text codes to confirm my account - Microsoft Q&A