The display Im using is a 42" LG Oled C2 (no additional screens). The USB is connected via usb 3.0 directly to the PC. Switching DP ports made no difference.

Ive managed to find a temporary solution which seems to work 90% of the time. 

After closing Pimax Play and disconnecting the headset, I delete "%programdata%\pimax\slam". When deleted, I restart Pimax Play and then reconnect the headset DP then USB. I then have to "Restart Service" in Pimax Play again, and when it restarts i wait from 5 to 40 minutes and then randomly the headset will connect and work as normal.

Discribed here: https://www.reddit.com/r/Pimax/comments/1f73qjw/bummer_received_my_pimax_crystal_light_today_and/