Sole Global Administrator locked out due to Microsoft Authenticator MFA

Hi @422102490
In this situation, the official way to regain access to your tenant is to contact Microsoft Support by phone.

I understand that, during the call, you may initially be connected to the Interactive Voice Response (IVR) system rather than a live support agent. Unfortunately, it is generally not possible to bypass this step. Based on information gathered from similar cases, you can use the script provided below to respond to the IVR prompts and help ensure that your call is routed appropriately.

The automated system will gather the necessary information, and once the process is complete, the call should be transferred to a support agent who can assist you in more detail.

If possible, find the support phone number for your region and follow the tips below to contact support effectively: Contact Microsoft Support 

When calling the support number, you may first hear a recorded message lasting approximately 30 seconds (for example, suggesting that you visit an online support page). You can simply wait for the menu options to be presented. Typically, selecting "1" for business users and then "1" again for technical support will guide you to the appropriate support flow. 

In some regions, the initial interaction may be handled entirely by an automated system. To help you prepare, below is an example of the questions you may receive and the recommended responses: 

What kind of problem are you experiencing? 

Answer: Authenticator 

What product are you using? 

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 administrator in the tenant. 

Do you need a Service Request? 

Answer: Yes. I need to open a support ticket. Please transfer me to the Data Protection team. 

Please note that this team is always overwhelmed, so you might need to wait for them to call you, this should take 3-10 working days. 

In case the phone support line is unavailable or unable to assist, you could consider to create a separate Microsoft 365 trial tenant and use it solely for submitting a support request. 

Here's how you can do it: 

Go to Microsoft 365 Business Plans & Pricing | Microsoft 365 (select "Try for free" in an enterprise subscription). 

Follow the instructions provided to create a trial tenant. 

Once the new tenant is created, go to the Microsoft 365 Admin Center > Help and Support to submit a support ticket, requesting to speak with the Data Protection Team on behalf of your original tenant. 

In the ticket description, you'll need to clearly explain that you're trying to regain access to your previous Microsoft 365 tenant as a single admin and that you need help from the Data Protection team. 

Note: 

This new trial tenant will not give you access to any data or settings from your original locked-down tenant. It only serves as a temporary means of contacting Microsoft support. 

Remember to cancel the trial subscription of the new tenant once the issue with the original account is resolved, to avoid unwanted charges. Cancel your Microsoft business subscription in the Microsoft 365 admin center | Microsoft Learn. 

I hope this information helps you successfully escalate your request and regain access to your tenant. If you have any updates or additional questions, please feel free to reply to this thread. I will be happy to continue assisting you.