HP Officejet Pro 8720 Shows offline when clearly online

A few more things, you can try, before "launching" your printer to the nether regions of space.

• Reset the printing system on your Mac to solve a problem - Apple Support
• Replace the USB cable, you are using with this printer, just to rule out a bad cable.
• Enable the printer's CUPS web interface. << Note that this may not work with all printers or all Macs, but worth a try. FYI, it did work with my 2023 M2 PRO mini, running macOS Sonoma
  • To enable it, enter the following command in the Terminal app: cupsctl WebInterface=yes
  • To access it, enter the following in a web browser: http://localhost:631/printers/
  • Enabling CUPS Printer Interface for Mac - vend

Hi,

An HP OfficeJet Pro 8720 is listed in About AirPrint - Apple Support. This means that the model in question should be compatible with macOS 14 Sonoma without the need for an additional driver, provided that the printer and the Mac computer are connected to the same network (Wi-Fi router).

Do not use USB if you want to try AirPrint.

AirPrint works with wireless (Wi-Fi) or wired (Ethernet) network connections, so you could choose to wire this printer model to one of the LAN ports of the Wi-Fi router instead. An Ethernet connection may be more stable, and would avoid some of the difficulties related to the use of Wi-Fi.

If necessary, if there is a problem with AirPrint, try a full power-cycle sequence (including the router):

Power off the Wi-Fi router, the HP printer, the Mac, and all other devices/computers. Wait two to three minutes. Power on the router. Wait two to three minutes. Power on the HP printer. Wait a minute or two. Power on the Mac. Finally, power on all other devices/computers.

http://h10032.www1.hp.com/ctg/Manual/c05050200.pdf#xref_airprint

Reset the printing system on your Mac to solve a problem – Apple Support (UK)

Add a printer to your printer list so you can use it on Mac – Apple Support (UK)

I suggest starting with this article: Solve printing problems on Mac - Apple Support

If that doesn't help, the next step would be to visit the HP support site to verify that you have the latest printer driver for this particular printer which is compatible with macOS Sonoma. Note that Apple does not provide these drivers, but only incorporates those that are provided to them by the printer manufacturers.

Should that still not help, I suggest that you perform a "factory default" reset on this printer. You may have to review your printer owner's guide for how to perform this reset.

With USB, the printer would require (reliable) drivers from the manufacturer. If this is a problem, you may want to at least try the driverless AirPrint technology instead. You do not have to connect wirelessly, but a router/switch would be used. As I indicated above, the connection printer to router could be through Ethernet cable. You could choose to connect the Mac mini through Ethernet or wirelessly. If you so wish, almost any old/spare router could be used for this printing only test/setup, and it could be placed next to the printer and Mac.

Sorry that you are having such trouble with your HP printer. FWIW ... although I have tried other brands, my experience with HP is 180º from yours. My "newest" HP printer (OfficeJet Pro 6970) is over 7 years old, and has been pretty much flawless. In my case, my printer is connected to my local network by Ethernet as is my Mac mini.