How to access global admin 365 account if locked out - authenticator not working!

Question

How to access global admin 365 account if locked out - authenticator not working!

Ross Abernethy 20

HELP!!! I'm a sole business owner with a 365 Business account. I'm completely locked out. I can't get authenticator to work and no matter what I do to try and sign in, it always asks for Authenticator to confirm a code, but I can't use Authenticator! I cannot access the 365 Admin centre. No apps or email available! I'm at my total wits end here. I've trued calling the phone numbers in UK and USA and declaring I am global admin and there is no other admin - only to have to wait and wait forever with no response.

I get the an error code 500121 when I try to sign in.

Please help me Microsoft!

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Answer accepted by question author

Michelle-N 20,745 Microsoft External Staff Moderator

Hi @Ross A

Thank you for reaching out to the Microsoft Q&A Forum.

I understand you are in an incredibly frustrating and stressful situation. Being completely locked out of your Microsoft 365 Business account is a critical issue that brings everything to a halt. The error code 500121 occurs when authentication failed as part of the multi-factor authentication (MFA) request, it may indicate a configuration or service error. Please find below a few steps that may help resolve the issue:

Because you are the only Global Administrator and you are completely locked out from the tenant. You may consider using the 24/7 support service available through Microsoft 365. You can initiate a support request by starting a free trial here: Microsoft 365 Business Plans and Pricing | Microsoft 365

User's image

Assuming that you have already created an account after registering a free trial and you can go to Microsoft 365 admin center and click "Help & support" icon to raise your ticket. The agent will be able to create a ticket for you under the affected tenant and then transfer this ticket to Data Protection team who could help you to regain access. User's image You can follow this link for more instructions: Get support - Microsoft 365 admin | Microsoft Learn . With this solution, you might be able to regain access to your admin portal in the old tenant. This will allow you to reassign MFA to your current device. 

We hope the details provided will assist you effectively.

If you found this response helpful, please consider selecting "Accept Answer" and giving it an upvote. Should you have any further questions or require clarification, feel free to click "Comment" to continue the discussion.

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.

Ross Abernethy 20 Reputation points

2025-07-01T07:27:37.7433333+00:00

Thanks but this also isn't a solution that works for me as I am unable to access the admin centre. Trying to login to that triggers an authenticator code I cannot verify because I can't get authenticator to work. I shall re-try the phone today but was on hold for 45 mins last night and gave up as it was 1am (called USA number from UK).
Ross Abernethy 20 Reputation points

2025-07-01T07:29:47.31+00:00

I do have Business Basic already, but of course can't access the emails related to that account for any specific numbers. The lesson for me as a sole owner is to have an admin account I truly only use for admin work, and a separate day-day user account for myself. I'll need to look into that once I get access restored.
Michelle-N 20,745 Reputation points Microsoft External Staff Moderator

2025-07-01T08:55:37.67+00:00

Hi @Ross A

You are absolutely right, set up two global administrators is the correct approach. This ensures that if you ever lose access to one account (for any reason, like an authenticator issue), you always have a backup method to regain access to your tenant.

With that in mind, and as we discussed before, the most direct path to recover your original Business Basic account is to use the free trial method to create a support ticket with Microsoft's data protection team. They are the only ones who can help with account recovery scenarios like this.

I truly hope you will consider trying this troubleshooting step, as it is the most reliable way to get your account back as quickly as possible. Please keep me updated on your progress!
Ross Abernethy 20 Reputation points

2025-07-01T08:57:35.16+00:00

I'm on the phone with MS Support now and they've raised a ticket with the data protection team, so your solution is the clearly the path. Thanks for responding. Hoepfully all sorted soon!
Michelle-N 20,745 Reputation points Microsoft External Staff Moderator

2025-07-02T04:29:03.1366667+00:00

Hi @Ross A

I'm just following up to ask if you have completed the process with the support team I guided you to. If your issue is now resolved, please mark it as an answer? Doing this will greatly help other community members who run into the same issue and can't use their authenticator to recover their account.

Contributions like yours help our community grow stronger and assist more people. Warm thanks!
Michelle-N 20,745 Reputation points Microsoft External Staff Moderator

2025-07-07T06:11:04.8333333+00:00

Hi @Camille Ross Ann Rudio

Not sure if you have any other updates on this issue? I'm always available to assist in any way I can.

2 additional answers

Your answer

Ross Abernethy 20 Reputation points

2025-07-01T07:27:37.7433333+00:00

Thanks but this also isn't a solution that works for me as I am unable to access the admin centre. Trying to login to that triggers an authenticator code I cannot verify because I can't get authenticator to work. I shall re-try the phone today but was on hold for 45 mins last night and gave up as it was 1am (called USA number from UK).
Ross Abernethy 20 Reputation points

2025-07-01T07:29:47.31+00:00

I do have Business Basic already, but of course can't access the emails related to that account for any specific numbers. The lesson for me as a sole owner is to have an admin account I truly only use for admin work, and a separate day-day user account for myself. I'll need to look into that once I get access restored.
Michelle-N 20,745 Reputation points Microsoft External Staff Moderator

2025-07-01T08:55:37.67+00:00

Hi @Ross A

You are absolutely right, set up two global administrators is the correct approach. This ensures that if you ever lose access to one account (for any reason, like an authenticator issue), you always have a backup method to regain access to your tenant.

With that in mind, and as we discussed before, the most direct path to recover your original Business Basic account is to use the free trial method to create a support ticket with Microsoft's data protection team. They are the only ones who can help with account recovery scenarios like this.

I truly hope you will consider trying this troubleshooting step, as it is the most reliable way to get your account back as quickly as possible. Please keep me updated on your progress!
Ross Abernethy 20 Reputation points

2025-07-01T08:57:35.16+00:00

I'm on the phone with MS Support now and they've raised a ticket with the data protection team, so your solution is the clearly the path. Thanks for responding. Hoepfully all sorted soon!
Michelle-N 20,745 Reputation points Microsoft External Staff Moderator

2025-07-02T04:29:03.1366667+00:00

Hi @Ross A

I'm just following up to ask if you have completed the process with the support team I guided you to. If your issue is now resolved, please mark it as an answer? Doing this will greatly help other community members who run into the same issue and can't use their authenticator to recover their account.

Contributions like yours help our community grow stronger and assist more people. Warm thanks!
Michelle-N 20,745 Reputation points Microsoft External Staff Moderator

2025-07-07T06:11:04.8333333+00:00

Hi @Camille Ross Ann Rudio

Not sure if you have any other updates on this issue? I'm always available to assist in any way I can.

Answer 1

Ross Abernethy 20

Thanks folks - I got it sorted by speaking to Microsoft. It took three days for them to get MFA fixed and acknowledged a backlog on the back office for issuing approvals. Lesson learned - I now have a separate Admin account from the account I use day-day. Id also like to see a clearer “account locked” status to avoid users wasting time trying to self-fix - have suggested this

Appreciate all the responses.

0 comments

Answer 2

Craig Long 19,025

Can you access your account at https://myaccount.microsoft.com/

If you go to "Security information" > "Update info", you will see the following: "Sign-in method when most advisable is unavailable." Click "Change" to change the default. I have also found that adding a new sign-in method becomes the default method.

You can even add a landline phone number if it's convenient for you.

Craig

Ross Abernethy 20 Reputation points

2025-07-01T07:10:23.24+00:00

Thanks, but no - I can't access because it always asks me to verify a code with authenticator and authenticator always asks me to ALSO verify a code with authenticator. It's so frustrating.