Unable to Access OneDrive for Business Due to Lost MFA/OTP Phone Number

Hello @DSM CAPITAL,

I’d like to clarify that as a forum moderator, I do not have access to user sign-in logs, cannot reset MFA, revoke access, or contact Microsoft Support on your behalf. Please consider me an end user as well, providing guidance based on experience and documented processes. 

To reset the MFA/OTP phone number associated with a business account from your side, you’ll need assistance from a Global Admin or Authentication Admin.

Could you please confirm if there is any admin account that is still accessible? If you're an end-user and haven’t yet reached out, here’s a helpful guide to locate your Microsoft 365 administrator: How do I find my Microsoft 365 admin? - Microsoft Support  

If you can find any admin account for help, kindly ask your administrator to follow the steps below:

• Go to Microsoft Entra Admin Center: https://entra.microsoft.com  
• Navigate to Entra ID > Users > All Users.  
• Select your user account.  
• Go to Authentication Methods.  
• Click "Require re-register multifactor authentication".  

This will reset your MFA settings. The next time you sign in, you’ll be prompted to set up the Authenticator app again using a QR code.  

If you are the only administrator in this tenant, you will need to contact the Microsoft Data Protection team, as they are the only group authorized and equipped with the necessary tools and verification procedures to confirm your identity and restore administrator access. 

Please try to find the related hotline number to call the frontline and let them raise a ticket for you (expand regions under Business Users to find supported number for your country): Customer service phone numbers - Microsoft Support 

Carefully follow this instruction to ask for Microsoft Data Protection team support:   

Depending on your country or region:

For some countries, when calling the support number, although there are about 30 seconds opening as something "you can visit the link...." But you can ignore this opening and wait until the option, then "1" as a business email user, "1" again for technical help.   

For some countries, it will be an automated conversation like:    

• First, when you call the hotline, it asks what kind of problem you are worried about.   
• Answered: Authenticator.   
• A: What kind of product are you using?   
• B: Microsoft 365 for business.   
• A confirmation: education or company account?   
• B: For company   
• A: Are you an administrator?   
• B: Yes.   
• A: Do you have the other admin in your organization?   
• B: No.   
• A: You need one.... Service request?   
• B: Yes   

Important note:

• If your subscription is from a partner or reseller, contact the reseller's support provider to help open a service request on behalf of you instead.   
• You may need to call multiple times before you are connected to a live support representative and can successfully create a support request with a ticket number for tracking.

Although I cannot help you reset your MFA setting directly, I’m happy to support you throughout the process. Once you’ve created the support request and received a ticket number, feel free to share it with me via private message. I can help you track the case and suggest next steps if needed. 

To access the private message, please refresh this page, you should see a pop-up at the top of your thread. Click on View message to review it. 

If you encounter any difficulties in contacting the frontline support, please feel free to let me know. Thank you and I wish you a great day!  

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.