Thank you very much for sending the log file.
We are currently analyzing it.
Could you also please send us the dxdiag info of your secondary machine, just run the dxdiag.exe then click “Save All Information”, then save the output file (dxdiag.txt).
And can you quickly try to connect with HTML5 viewer on your secondary machine, just open a web browser e.g. Google Chrome then go to http://viewer.spacedesk.net/ and try to connect to your primary machine’s IP address.
Then let us know if you also get a black screen.
If it also did not work with HTML5 viewer, are you willing to help us further investigate the cause of the problem by checking the network packets (on both server and client side) using wireshark app?