Try disabling Force HW in the addon settings.
I have the same issue as stConners even if i disable "Force HW" (and restart). It pairs, connects but didnt establish the stream.
System:
Asus chromebox with LibreELEC 7.0.2, Moonlight 7.0.101
Log:
Moonlight Embedded 2.2.0 (SDL;VDPAU;PULSE;CEC)
Searching for server...
Connect to 192.168.1.2...
NVIDIA GeForce GTX 970, GFE 2.11.4.0 (protocol version 7)
SDL: could not create window - exiting
Any idears?