Why is my MacBook Pro unable to print via Wi-Fi?

Hello again,

Regarding Wi-Fi, have you checked whether the printer is properly connected to the router? It is probably safe to assume that this model can use 2.4 GHz only, so a wireless connection to a 5 GHz network would fail. Many modern routers have an automatic device detection and band selection, which does not always work as intended, If so, one may have to split/rename bands and manually make sure that the correct band is used.

You could also just connect the printer by Ethernet cable to one of the LAN ports of the Wi-Fi router for a quick test.

Furthermore, the MX870 was on the Gutenprint list of printers. However, according to a message at https://gimp-print.sourceforge.io/, macOS is no longer supported. Were you possibly using a Gutenprint driver?

Anyway, if it is not a Wi-Fi/router issue, if the problem is driver-related, and if no driver of any origin is compatible with this printer model under macOS 14.6.1 Sonoma, you may have to look for another solution.

There are still Windows drivers for the MX870, so if absolutely necessary, you could use the printer with a PC. Temporarily, you could print to/save as PDF on the MacBook Pro, and then transfer the files to a PC for printing.

Yet another alternative could perhaps be to use an older Mac computer (with compatible drivers for the MX870). If this old Mac is running OS X 10.9 Mavericks or later, a third-party Mac app Printopia may (as a print server) even allow AirPrint-like printing, at least from iPhones and iPads.

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)

Thank you for the information. At least according to Canon's support page below, the MX870 has been retired, and product support is no longer available. Download links are still there, but the latest CUPS printer drivers appear to be for OS X 10.11 El Capitan. So, I have to assume that these drivers either have continued to work with more modern macOS versions or that you are using different drivers.

https://www.usa.canon.com/support/p/pixma-mx870

Also, the MX870 is not listed as an AirPrint-supported model.

About AirPrint - Apple Support

Is it possible that "authentication" is not related to the Wi-Fi network but to an internal printer setting or to a driver?

Have you checked whether a printer firmware update has been made available earlier?

First of all, information about the printer make and exact model would help.

Also, any changes with the Wi-Fi router? Have you tried the usual things, like a full power-cycle sequence (including the router, the printer and all connected computers and devices)?

rickat wrote:

I am suddenly unable to print via wifi with my MacBook Pro. When I start a print job it stops with the message that the printer requires "authentication" in order to proceed. No other information is provided and I can't print anything until this problem is solved. I am running macOS Sonoma 14.6.1 and I can't find anything in Settings or in my Keychain that will allow me to fix this. Also, none of the instructions currently available either here or elsewhere work. Does anyone have a real solution?

Thanks,

rickat

yea reach out to the printer manufacture support or look at their help site for authentication.