Foreman - Azure trouble


I'm having trouble spinning up Azure VMs using Foreman with the
foreman_azure plugin. I have successfully been managing the VM lifecycle
with within XenServer, using XenServer plugin, but I am failing with Azure.

I'm following the guide here
Foreman :: Plugin Manuals . I have
successfully linked Foreman with Azure using the certificate and I'm
confident it's talking to Azure ok, because the 'test connection' button
works, and I can list all the Azure OS images.

But when trying to create a host, I get a 'Choose an operating system and
image first' warning (I've attached as screenshot-1), despite the fact I
have done so (screenshot-2).

I also get this same message when I try to set up a 'Compute profile'
within the 'Compute Resources' screen.

I'm not sure if I am missing something or if there is a bug. Is anyone
using this Azure plugin successfully with Foreman?