I have been playing around with this and so far I am very impressed. We have some bespoke software for our industry and we have not long moved to Azure to host our RemoteApps. Not long after, Microsoft announced this Virtual Desktop Service so I have been having a play.
1. First time, managed to deploy my remote apps, use the Web Based connection and the RDP tool which you can download. Had no issues.
2. I noticed that I could have better naming conventions etc so I decided to go again!
3. This time, I can access the RemoteApps via the web browser but when I use the RDP tool I get the attached error.
Any ideas why? I look in certificates etc and could not see anything.
Added another user and that signed in OK and had access to the app.
@JonBurgess : Do you have Intune (or other MDM solutions) that require the device to be joined to the organization? Unfortunately, these errors are not specific to Windows Virtual Desktop, but more about the "work or school accounts" and trying to register the device to your organization.