Can you further describe the problem?
Viewer cannot discover? Did you get an error code upon connect?
For assistance, please also check the Troubleshooting chapter in the user manual.
If the troubleshooting did not help, please open the spacedesk Driver Console in your primary machine, click 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.