Windows Server 2016 Essentials, or Windows Server 2016 Standard/Datacenter with the Windows Server Essentials Experience (WSEE) server role, MUST either be or see a DC. This limitation has nothing to do with my software (nor with RemoteApp per se), but is simply a requirement of the underlying “Essentials” features of the server operating system itself.

Basically, if you want to use WSE RemoteApp 2016 on Windows Server 2016 Standard/Datacenter (with the WSEE server role) without the server needing to be a domain controller, then you can join it to a second server that is acting as the primary domain controller. For more information, see the “Additional Information (Advanced)” section on the WSE RemoteApp 2016 home page.

EDIT: If you simply want to make a Windows Server Essentials server behave like Windows Home Server 2011 did (which was based on Windows Server 2008 R2 and wasn’t a DC), then you can always just use Microsoft’s “SkipDomainJoin” registry setting in order to prevent your client computers from having to join the Essentials server’s domain as described in the following articles:

How to make Windows Server 2012 R2 Essentials client connector install behave just like Windows Home Server

Connect computers to a Windows Server Essentials server without joining the domain

WSE RemoteApp 2016 is fully compatible with such a scenario, and would basically amount to you being able to run Windows Server 2016 Essentials, or Windows Server 2016 Standard/Datacenter (with the WSEE server role), as a domain controller, without requiring you to have any of your client computers joined to the domain. This is exactly how I run my own home and small business Essentials servers.