I am unable to log in to my Microsoft 365 account as I recently changed my phone

Hi @anushka udayanga 

Thank you for posting your question in the Microsoft Q&A forum.   

Regarding your issue, if you are the only global admin and can't access Microsoft 365 admin center I suggest contacting Microsoft Support for help Customer service phone numbers - Microsoft Support 

Please remember to provide them with your account details and explain the situation. Be ready to provide:     

• The company name used during subscription    
• Billing email address (even if it’s a personal Microsoft account)    
• Payment method details (last 4 digits of the card, billing address)    
• Any subscription ID or invoice numbers from billing email    

To make the process smoother, here’s an example of how to respond when speaking to the automated system (IVR):     

IVR: What kind of problem are you concerned about?     

You:  Authenticator.    

IVR: What kind of product do you use?     

You: Office 365 for business.     

IVR: Education or Company account?     

You: For companies     

IVR: Are you an administrator?     

You: Yes.     

IVR: Do you have the other administrator in your organization?     

You: No.     

IVR: Do you need a... Service request?     

You: Yes     

These prompts help direct your call to the right support team more quickly, especially when dealing with account lockouts and authentication issues.    

If you still cannot reach to agent, there is still a workaround, you might consider registering for a new tenant by signing up for a trial subscription via this link Compare All Microsoft 365 Plans | Microsoft. This would allow you to create a new tenant following the provided prompts.    

Once set up, you can access the admin console of the new tenant by logging into admin center and follow the steps in this article Get support - Microsoft 365 admin and submit a support ticket requesting to speak with the Data Protection team on behalf of your previous tenant.    

Please remember to cancel the trial subscription once your issue is resolved to avoid any unintended charges.

As forum moderators, we don’t have access to the detailed system needed to troubleshoot this effectively due to privacy and security constraints. To quickly resolve this and regain access, the most effective step is to contact Microsoft Support Team directly. Only they have the ability to help with your Authenticator issue.    

Hopefully it will work for you and if you have any other questions or need further assistance, feel free to ask.

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

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