Thanks for the initial info.
Can you please check your WiFi router if there’s a client/WiFi/AP isolation setting enabled?
This setting prevents direct communication between connected devices/computers.
By the way, we cannot open your attached diagnostic logs, please re-attach it as *.zip file.
PS: We moved your post in a separate topic to avoid confusion.
Thanks for sending your diagnostic logs and for checking the router settings.
Can you easily try to ping the IP address of your secondary device from your primary machine (vice versa) to check if both PC/devices are reachable to each other?
By the way, which spacedesk Viewer app are you using? Is it Android/iOS/Windows?