Error message:
"Details: AADSTS50020: User account '{EmailHidden}' from identity provider 'live.com' does not exist in tenant 'Microsoft Services' and cannot access the application 'c44b4083-3bb0-49c1-b47d-974e53cbdf3c'(Azure Portal) in that tenant. The account needs to be added as an external user in the tenant first. Sign out and sign in again with a different Azure Active Directory user account."
This error message can occur if you have a subscription that is recently expired, inactive, or orphaned. To resolve this, you will either need to claim a new Azure subscription or transfer the subscription to a new account. I would recommend opening a support case for this as you may need internal help to resolve this (depending on which issue this is).
Here is a link that also provides some helpful information on orphaned accounts. https://learn.microsoft.com/en-us/azure/devops/organizations/accounts/resolve-orphaned-organization?view=azure-devops#:~:text=An%20organization%20is%20considered%20orphaned%20when%20the%20organization,way%20of%20transferring%20administrator%20rights%20to%20another%20user.
If you send me an email (included in the private comment), I will gladly open a one-time free support case to help resolve this issue.
There are other possibilities for this error message, but most often I see it because of the subscription issue. However, I would also recommend trying the following:
That message can happen if you have a personal "Microsoft" account using the same email address as your O365 "Work or School" account. To resolve this, go to microsoft.com/accounts using an incognito browser so that no credentials carry over, and choose the Microsoft account when logging in.