Thank you for posting this in Microsoft Q&A.
As I understand you are unable to login to Azure portal and you are getting "AADSTS16000" error which is saying your account could not be found in the tenant.
Since you mentioned that you have set up your account recently, there are possibilities that you are trying to login to different tenant.
Try logging in to below URL,
https://portal.azure.com/<domain.onmicrosoft.com>
Replace "domain.onmicrosoft.com" in above URL with the actual tenant. Enter you account credentials and confirm if this solution works.
If this is not solving the issue, then you will have to contact Microsoft support team to get your global admin account unblocked,
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.
Create a ticket with Microsoft support team. Give them the tenant ID which is locked out in your description. Tell them that no admin account has access anymore and your partners also have no access anymore.
Once you create a ticket with support team you will have to work with our data protection team. You will have to first prove your identity against your tenant for security purpose. Post that this team will help you with help you in getting access to your tenant or unlock your account depending on your scenario.
Also, for the future, you can create an emergency access account (break glass) in Azure AD. This account will help prevent being accidentally locked out of your Azure Active Directory (Azure AD) organization because you can't sign in for any reason.
https://docs.microsoft.com/en-us/azure/active-directory/roles/security-emergency-access
Let me know if you have any further questions on this.
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