Unable to connect to RDP from Android using AzureAD credentials

Question

I'm trying to use the Android RDP client to connect to a machine with AzureAD credentials however it constantly rejects what I send. Does anyone know of any special options I need to do to make this work?

I've tried the following:

azuread\[e-mail] azuread\user (retrieved from whoami) [e-mail]

Any ideas? It works from Windows to Windows, just not Android to Windows.

ta, Justin