On some situations, having a VPN connection present on either primary or secondary machine prevents the network discovery process between spacedesk server and client, which results to „Cannot Detect Primary Machine“ or „Error code 1-0“ in spacedesk viewer apps.
There are various workaround that can fix this problem without completely disabling the VPN connection.
1. If VPN app has user interface with configuration settings that will let users select a specific apps to not use VPN, just add the C:\Windows\System32\spacedeskService.exe on this exception list.
2. Run „ncpa.cpl“, right-click the Ethernet or WiFi network icon then open the Properties window. Click on the Sharing tab and check the „Allow other network users to connect through this computer’s internet connection“ box.