RemoteApp sporadic failure

We have a new Windows 2016 server with RDS installed.

I am encountering a sporadic failure to launch our RemoteApp. Regular Remote Desktop sessions are connecting just fine, hoewever.

When RemoteApp fails...

The client receives this message: "Because of a protocol error (code: 0x112f), the remote session will be disconnected. Please try connecting to the remote computer again."

The server shows nothing in the App, Security or System logs. However, the Operational log of RemoteDesktopServices-RdpCoreTS will show the following error during the connection. Immediately afterwards, the logs show the session disconnecting. "'Failed GetConnectionProperty' in CUMRDPConnection::QueryProperty at 2735 err=[0x80004001]"

After several informational messages as it tears down the session, another error follows: "'Failed CreateVirtualChannel call on this Connections Stack' in CUMRDPConnection::CreateVirtualChannel at 2349 err=[0xd0000001]"

Both errors are EventID 227.

Google and TechNet are failing me here. I'm hoping to avoid calling in Microsoft on this one.

Any ideas?

Despite using GPOs, the RemoteFX stays enabled. Disable via registry.

HKLM\System\CurrrentControlSet\Control\Terminal Server\WinStations fEnableRemoteFXAdvancedRemoteApp Will show set to 1. Change to 0 and reboot.