If the app is unable to find the printer, on a computer, you will have to find either the Printer Preferences on a Mac or right-click on the printer in the Devices and Printers in order to access the Printer Properties and turn on the sharing feature of this printer in order for the app to find it.
If this doesn't answer your question, do you have a computer and if so, is it Windows or Mac?
I hope this helps!
Don't forgot to say thanks by giving "Kudos" if I helped solve your problem.
When a solution is found please mark the post that solves your issue.