Both Windows Firewall and the anti-virus firewall were enabled. (This is strange in itself: normally, an anti-virus program disables Windows Firewall.) Disabling Windows Firewall, rebooting, and reinstalling the printersoftware finally got the wireless printer working again.
The government may simply insist that 3D printer manufacturers install software that prevents printing of a hollow cylinder of a certain size, a firing pin, or a certain type of spring.