The sole global administrator is locked out due to an MFA loop—caused by having only the "push notification" mode enabled in the Authenticator app with no fallback authentication method—and requires assistance to reset their verification settings.

Hello @jaylen chan

Based on the information you shared, I understand that you are having an issue related to your Microsoft Authenticator app, which is not working as expected and you have no alternative MFA method such as Phone or email.

Since you are the only user or administrator of the tenant, you will need to contact the Microsoft Support Data Protection team to have your MFA reset. Please locate the appropriate Microsoft support hotline for work account and contact the frontline support team so they can raise a ticket on your behalf: Customer service phone numbers - Microsoft Support    

Please note that this is a user-to-user support forum. Only Data Protection team can help you to revoke the session and reset your password, account, MFA...

Data Protection Team will first verify your ownership of the account and revoke your MFA once confirmed. After that, you can set up the Microsoft Authenticator app again on your new device. 

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

(While calling, you can ignore the 30-second introduction that says "you can visit the link..." and wait until you are presented with the options. Press "1" as a business email user, and again "1" for technical help.)      

In some regions, the initial interaction may be automated, 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.

If you can't contact Microsoft Support by phone, you can try creating a new trial tenant using the link below: Microsoft 365 Business Plans and Pricing | Microsoft 365 After you fill out and submit the sign-up form, you'll have access to the Microsoft 365 admin center.

Once you've gained access, contact the Microsoft support team by following the guidance in the following document to create a support ticket: Get support - Microsoft 365 admin | Microsoft Learn

When submitting a support ticket, please clearly indicate that the issue involves another tenant and provide as much information as possible about that tenant, including the tenant domain, domain registration details, administrator username... Providing this information upfront will help the support team validate the tenant relationship and investigate the issue more efficiently.

After the issue is successfully resolved, remember to cancel your trial subscription by following the instructions in the following document: Cancel your Microsoft business subscription in the Microsoft 365 admin center | Microsoft Learn

I hope this information helps you move forward with your support request and that the issue can be resolved soon.