Auto Launch Published App Wyse 3040

Hi community. Hoping someone can help me. Apologies if this has been covered before, but I’m struggling to find the relevant info here or elsewhere online.

We have some new Dell WYSE 3040 thin clients that we are going to use to replace some legacy WYSE thin clients that are running on a 2003 Citrix Farm which is to be decommissioned.

We have a 2012R2 RDS environment (SRV01 – RDCB, RDLS, RDWA, RDSH SRV02 – RDSH) and a number of RemoteApps that we deploy to users within our Windows Domain. What I require the WYSE 3040 clients to do is boot and auto-launch one of the published RemoteApps.

We are not using WDM or WMS as we only have a handful of Thin Clients, so are happy to configure these manually, individually if needed or via an ini generator. We just need a simple setup to auto-launch a single RemoteApp.

Would somebody be able to point me in the right direction of how to do this as I cannot get my WYSE to connect to my broker server, I simply get RD Broker sign on failed. I know the credentials are correct as I can create an RDP connection to launch a full desktop.

I have tried hostname and ip of my broker server, tried with and without the SSL certificate added. Someone mentioned elsewhere I need the root certificate? Not sure if anyone can confirm or deny?

Dell WYSE 3040 are running ThinOS 8.6_013

Windows Server 2012 R2 RDS