If you are the sole administrator within your Azure subscription and have lost access to your Azure portal due to the loss of your authenticator, you can attempt the following step to regain access:
- Microsoft Account Recovery: Visit the Microsoft Account recovery page at https://account.live.com/acsr.
For further assistance and guidance, you can refer to the Microsoft support article available at https://support.microsoft.com/en-us/account-billing/help-with-the-microsoft-account-recovery-form-b19c02d1-a782-dee6-93c3-dc8113b20c42.