I have an Azure Active Directory (contosodev.net) with Azure Active Directory Domain Services. This directory is a separate directory from our main one (contoso.net). I can add external users as members or guests (such as email@example.com), but these users cannot RDP into a VM or authenticate with it, even if I am able to add them to the Remote Desktop Users group on the VM (e.g., it shows up as contosodev\david).
Is this possible? Or is it only possible for users on the actual domain to authenticate?
I have already changed the passwords after enabling the hash synchronization and the normal domain accounts work fine. I am asking because I have contractors that I would like to add under their gmail accounts, but let them RDP, otherwise I will create them actual domain accounts.