Cannot turn on "Multi-Tenant" for Azure AD Authentication

Question

I've gone through several guides and spent several hours, but I can not seem to get Azure AD authentication working in my simple app. I am trying to turn on "Application is multi-tenant" in my Azure Active Directory, and I get the following error:

The App ID URI is not available. The App ID URI must be from a verified domain within your organization's directory.

How can I change my Application to have the same domain as my Azure AD? (*.onmicrosoft.com).

Am I doing something wrong here?

Answer 1

The message is pretty descriptive.

First you have to take a verified domain which is linked to your Azure AD. You can take it from the Domains tab on your Active Directory management page:

Then your AppID URI must be within any of those:

Only then you will be able to make your app Multi Tenant.