Could you please check the following:
1. Check your WiFi router settings if it has client isolation enabled. This setting prevents direct communication between connected devices/computers.
2. Do you have VPN (Virtual Private Network) active?
3. Do you have third party firewall/antivirus software on your primary machine?
4. When you said you attempted a direct connection by wire, is it USB tethering connection?
5. Check on your iPad Settings -> Privacy -> Local Network, if spacedesk is on the list and enabled?
For assistance, please also refer to the Troubleshooting -> Network Connection chapter in the user manual https://www.spacedesk.net/user-manual/#item_489.
If the above suggestions did not help, please send us the diagnostic files of your primary machine.
Just open the spacedesk Driver Console -> Diagnostics -> Save All Information.
PS: Saving all information will take a few seconds, then please send us the whole folder which contains all the diagnostic logs collected.
Please right-click the folder -> Send to -> Compressed (zipped) folder, then attach the *.zip file in your next reply.