Hi Jeff Wang,
The issue you are experiencing the error AADSTS16000 and being unable to access even the Billing section is a known scenario that can occur after all subscriptions are removed or canceled from an Azure account. When you delete your only Azure subscription, your account may lose its connection to an Azure Active Directory (Entra ID) tenant. This means your account is no longer recognized as part of any tenant. As a result, you won’t be able to access resources, billing information, or even basic features in the Azure portal. The portal may ask you to sign in with a different account because your current account is not linked to an active tenant. The recommended solution is to create a new tenant and subscription using your existing Microsoft account, which will restore your access and allow you to manage billing and payment methods.
Open an incognito or private browser window to avoid any cached sessions and go to the Azure Free Account page and sign up for a new tenant and subscription using your existing Microsoft account (the one tied to your credit card). This process will create a new Azure Active Directory (Entra ID) tenant, and you will automatically become the Global Administrator of this new tenant, once the new tenant is created, you will regain access to the Azure portal and the Billing section.
After you regain access, go to the Billing and Cost Management section, navigate to Payment Methods and remove your credit card or update your billing preferences. This ensures you will not be charged for any future services. Link: https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/cancel-azure-subscription
Confirm that your old subscription is indeed canceled and not just disabled.
To make sure there is no "Interaction Required" Error, log out of the Azure portal completely and clear your browser cache or try accessing the portal in an incognito window, re-sign in with your Azure account and make sure you are using the same account tied to your billing profile. If prompted to sign into a specific tenant, follow the instructions to grant access.
For additional reference:
Hope the above provided information help you resolve the issue, if you have any further concerns or queries, please feel free to reach out to us.
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