Apple Bug Reporter Item: 46807004
Routed printing id broken in macOS Mojave limiting printing to only devices on a user's local subnet. This affects Bonjour, LPP, and Windows printing, all models of printers, and any model of Mac. The issues occur on systems that have been upgraded to Mojave or brand new Macs out of the box.
Printing to devices on the same subnet still works with Bonjour etc, but the printing to printers on different subnets fails, even though you can ping them or open their web page.
This is not a driver or configuration issue that the user can fix. It is a defect in Mojave that must be fixed by Apple.