We just got done troubleshooting issues with unattended systems not connecting back to the screenconnect server after a reboot. I ended up finding that Trend Micro worryfree business was playing with port 80 traffic which my relay service is on. I ended up having to whitelist the ip of my screenconnect server in order for things to work correctly. If you are having an issue similar to this, make sure you check the antivirus on the client side to see if it is messing with your relay traffic!