Azure AD requires that the user's account name is returned in the NameID in the format of Down-Level Logon Name.
https://docs.microsoft.com/en-us/windows/win32/secauthn/user-name-formats
In the DualShield Admin Console, find the Service Provider, e.g. "ADFS".
In the context menu of the service provider, select "Edit"
Change the "NameID Format" to "Down Level Logon Name"
Click Save