Dear Titefleur o_O,
Thank you for reaching out to Microsoft Q&A forum.
I’m truly sorry for the inconvenience and frustration this situation has caused. Based on the information you shared, it appears that you are currently unable to access your tenant because you are the only administrator, and you no longer have access to the Authenticator app, with no alternative MFA method configured.
To gain access to your account again when you are the only admin of the tenant, our Data Protection team can support you in this matter by using established tools and processes to verify your identity and help restore secure access to your administrator account.
Please note that forum moderators have no control over user accounts, especially when it comes to logging in to your account, resetting your password, changing your access, etc.
Therefore, please try to find the related hotline number to call the frontline let them raise a ticket for you: Customer service phone numbers - Microsoft 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: 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 your organization's Office 365 Business/Education subscription is from a partner or reseller, and the global administrator is unable to open a service request on your end, contact the reseller's support provider to help open a service request on behalf of you instead.
I hope this information helps you take the right steps to regain access to your account. If you have any updates or additional details, please feel free to leave a comment under this post. I’ll be happy to assist further within my scope.
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