The error message AADSTS5000225: This tenant has been blocked due to inactivity indicates that the tenant has been made inaccessible due to a lack of activity. This is a common policy to help reduce unnecessary expenses for tenants that are no longer in use. If you encounter this error, you will need to reactivate your tenant within 20 days of it entering an inactive state. After this period, the tenant will be deleted and cannot be recovered.
To reactivate your tenant, the administrator can reach out to Microsoft support for assistance. If you do not plan to reactivate the tenant, it will be deleted after the 20-day period.
For further details on handling an inaccessible tenant, you can refer to the relevant Microsoft documentation.