Tenant lockout – only Global Admin lost MFA device (Authenticator)

Hi

I’m truly sorry to hear that you’re currently unable to sign in.

From what you've described, it sounds like your Multi-Factor Authentication (MFA) setup may need to be reset. This can sometimes happen after switching to a new device, replacing a phone, or reinstalling the Microsoft Authenticator app. Since your new device hasn't been registered yet, the authentication requests may still be linked to your previous device, which can leave you stuck in a sign-in loop.

If your account is also an admin account and there are no other available global administrators in your tenant, then the only way to regain access is contact Microsoft support. Please try locating the appropriate hotline for your region here: Customer service phone numbers - Microsoft Support 

In this situation, the Microsoft Data Protection team has tools and processes in place to verify identity and regain access to administrator accounts. 

Here are some tips and an example of a prompt to help you navigate the IVR more effectively: 

(When you call the support number, you may hear an introduction of about 30 seconds such as "you can visit the link...". You can ignore this introduction and wait until you are presented with the options. Then press "1" as a business email user, and again "1" for technical help.)   

In some regions, the initial interaction may be automated, so here’s a general idea of how the conversation might go to help you prepare:     

• What kind of problem are you experiencing?        
• Answer: Authenticator        
• What products do you use?        
• Answer: Office 365 for business        
• Is this for an education or company account?        
• Answer: For companies        
• Are you an administrator?        
• Answer: Yes        
• Are there any other administrators in your organization?        
• Answer: No. I am the only admin in my tenant         
• Do you need a... Service request?         
• Answer: Yes. I need to create a ticket. Please send me direct to the Data Protection Teams.     

During the phone call, you will need to provide the information associated with your subscription, such as your company name, billing details, phone number, and an alternate email address, etc. This information allows the Data Protection team to verify your identity and securely assist you in regaining access to your administrator account.     

In case you are unable to contact the frontline support:

Consider signing up for a trial subscription to create a new tenant: Microsoft 365 Business Plans and Pricing | Microsoft 365

Once set up, you can access the new tenant's admin console and submit a support ticket to speak with the data protection team on behalf of the previous tenant. Once your issue is resolved, please remember to cancel the trial subscription to avoid any unintended charges.

If your organization's subscription is from a partner or reseller: Contact the reseller's support provider to help open a service request on behalf of you instead.

I hope this helps point you in the right direction. If you have any updates or additional questions, feel free to reply back and I'll do my best to assist further.

Best regards.

If this answer was helpful, please click "Yes". If you have any further questions about this answer, please click "Comment".