Microsoft 365 Education tenant-wide sign-in failure – Global Administrator also unable to sign in

Hi @Lâm Nguyễn Văn,

Since this is a user-to-user community forum, community members here are fellow users and do not have access to your tenant. They cannot create support tickets on your behalf, nor can they directly investigate or resolve a tenant-wide authentication issue. You will need to contact Microsoft Support directly for further assistance.

The best next step is to contact Microsoft Support by phone so that the frontline support team can create a case and route it to the Data Protection team if necessary. You can find the appropriate support number for your region here: Contact Microsoft customer support

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: Microsoft 365 Education

Is this for an education or company account?

Answer: For education

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 call, be prepared to provide information associated with your subscription, such as your organization name, billing details, phone number, alternate email address, and any other information requested for identity verification. This helps the Data Protection team confirm ownership of the tenant and securely assist you with recovering access to the administrator account.

If calling support has not been successful so far, there is another workaround you may consider. You can create a new Microsoft 365 trial tenant here: Microsoft 365 Business Plans and Pricing | Microsoft 365

Once the new tenant is created, you’ll be able to sign in to the Microsoft 365 admin center and submit a support ticket from there. In your request, clearly explain that you need help with regaining access to an administrator account in your original tenant and ask to be routed to the Data Protection team. This approach typically ensures that the ticket is properly assigned and handled by a real support engineer rather than remaining stuck in automated flows or disconnected mid-process.

Note: When choosing a contact method for the support case, you may also select Email if you prefer communicating in writing. Once your original issue has been resolved, remember to cancel the trial subscription if you no longer need it to avoid any unintended charges.

I hope the information above proves helpful and helps you reach the appropriate support team so you can move forward with regaining access to your organization.

Thank you for taking the time to read through my suggestions. If anything is unclear or if you have any updates along the way, please feel free to reply back. I'll be happy to clarify further if I can.

This is definitely a critical situation. Since the entire tenant, including the Global Administrator, is affected, Microsoft Support should be contacted through an official support channel outside the affected tenant. Be prepared to provide the tenant domain, organization details, affected accounts, and the approximate time the issue started. Hopefully Microsoft can verify ownership and investigate the tenant-level authentication problem quickly.