If you're seeing PORT ERROR on Windows, it's likely that the driver did not get installed correctly for some reason. To fix this, navigate to
then right click on the file
zttap300.inf and select "Install" from the menu.
Note: The folder
C:\ProgramData is hidden by default and requires Administrator privileges to access.
If you have other VPN or similar apps that require network drivers, you may want to try uninstalling them, probably rebooting, and reinstalling ZeroTier.