I created a Microsoft Entra External ID tenant (experimenting / learning) via the Entra portal (https://entra.microsoft.com) using my MSA account (whatever@outlook.com) which I use with the Azure portal (https://azure.microsoft.com).

Using the Entra portal, I added a new local user as the Global Administrator to the tenant and removed (deleted) my MSA account from the tenant (which was added automatically when the tenant was created).

After a couple of days, I then deleted the tenant via the Entra Portal (using the local user / Global Administrator).  The tenant was deleted successfully in the Entra Portal (no longer listed); however, I now have an orphaned External ID resource name in my Azure portal that cannot be deleted.  The resource type is “External Configuration Tenant” and when I click on the External tenant name (which no longer exists), the Azure portal displays the following error:

AADSTS90002: Tenant '299e2dbf-061c-479c-946a-35d5a8059f1c' not found. Check to make sure you have the correct tenant ID and are signing into the correct cloud. Check with your subscription administrator, this may happen if there are no active subscriptions for the tenant.

The error makes sense, as the External Tenant is not found because it was deleted in the Entra portal, but the resource associated with it (in the Azure portal) is still listed, but cannot be deleted.  One would think that if a resource name points to an entity that no longer exists, that resource name should be able to be deleted – but it is impossible to delete via the Azure portal.

How does one delete “orphaned resource names” in the Azure portal?