Hello @Alex Martinez ,
Welcome to the Microsoft Q&A platform.
Based on your description, I understand that you're the only admin for your company, and you're currently unable to log into your account because you're unable to access the Authenticator app on your previous phone. Since the system is asking for a code, but you no longer have access to it, you're facing a circular issue where you're unable to authenticate.
As you're the only admin for your company, this situation is considered a tenant lockout scenario.
If you are the only global admin on the account and are blocked entirely, you can reach out to our support team. You can look into below article to get support numbers depending on your country.
https://support.microsoft.com/en-us/topic/global-customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2
or creating a ticket through a different account: https://learn.microsoft.com/en-us/microsoft-365/admin/get-help-support?view=o365-worldwide#phone-support
Thank you for sharing required details over Private message.
The issue relates to a tenant lockout situation where no other global admin in the tenant has the necessary admin rights to re-register MFA.
To resolve this, we engaged our Data Protection team through a support ticket. Please connect with our support team via the ticket, and they will assist you in resolving the issue.
I hope this information is helpful. Please feel free to reach out if you have any further questions.
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