A free program from Microsoft that provides developers with the tools, resources, and sandbox environments needed to build solutions for Microsoft 365.
First, I’d like to clarify that this is a user‑to‑user support forum. Moderators participating here do not have access to backend systems, nor can we directly intervene in Microsoft product functionality. Our role is limited to providing technical guidance and sharing best‑practice recommendations based on reported issues, requests, and scenarios.
I’m truly sorry to hear about the frustration you’re experiencing. I understand that you’ve lost access to the Microsoft Authenticator app and are now locked out of the sole Global Admin account for your Microsoft 365 Developer E5 tenant.
May I ask whether you previously configured any alternate sign‑in or MFA methods, such as SMS or phone call?
If so, you may be able to regain access by selecting “Sign in another way” during the authentication process.
If not, in this situation there are only two official paths available to regain access to the tenant:
1.Please visit the following page and reach out to phone number via: Customer service phone numbers - Microsoft Support
From what I know, you will need to get past the initial AI system to reach the live support team. You can refer to the guide below for tips on how to get through more easily:
2.If method 1 is not working, please follow this link to create a trial tenant: https://www.microsoft.com/en-us/microsoft-365/business/microsoft-365-business-basic?msockid=3eb6980… , after that you will be able to access to Microsoft 365 Admin Center to raise the ticket
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.
Please mention that you are raising ticket on behalf of the affected tenant that you do not have access to. The support team will help you to create ticket on the affected tenant then later on the Microsoft Data Protection team will assist you.
Note: This process will take more time than usual (7-14 working days) for your account to get access again as Data Protection is always overwhelmed with the number of tickets. As I am forum moderator, I do not have access to Microsoft internal system to assist or push this process to be quicker.
On the other hand, if you do create the trial and it resolves the issue, please remember to cancel the subscription afterward to avoid any related charges.
I hope my information is helpful. Please give me any updates once you get this resolved.
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