Canon G6020 printer stopped working in MacOS Sequoia

If necessary, a simplified printer-to-router setup method (WPS) is available (if the router supports it):

https://support.usa.canon.com/kb/s/article/ART175503 (push button)

or

https://support.usa.canon.com/kb/s/article/ART176532 (PIN)

If a wireless connection problem printer-to-router is suspected for some reason, you could wire the G6020 printer by Ethernet cable to one of the LAN ports of the Wi-Fi router instead, at least for a comparative test.

The Canon G6020 is listed as a supported printer in About AirPrint - Apple Support. Provided that the printer and your Mac computer are connected to the same network (Wi-Fi router), it should be possible to print without additional software/drivers.

After checking all settings/connections, you may want to try a full power-cycle sequence (do not forget the Wi-Fi router):

• Power off the Wi-Fi router, the printer, the iMac, any iPhones/iPads, and all other devices/computers.
• Wait two to three minutes.
• Power on the router.
• Wait two to three minutes.
• Power on the printer.
• Wait a minute or two.
• Power on the iMac, any iPhones/iPads, and all other devices/computers.

Canon PIXMA G6020

If the above reply doesn’t resolve this…

Using the AirPrint printing path, or using the Canon add-on drivers? Switched to the other printing path?

https://www.usa.canon.com/support/wireless-help

https://support.usa.canon.com/kb/s/article/ART142242

Current printer firmware installed?

https://downloads.canon.com/hsg2023/ijprinters/manuals/G6000ser_OnlineManual_Mac_EN_V01.pdf page 179

or https://support.usa.canon.com/kb/s/article/ART183640

Based on page 109, it appears there might be an embedded web server in that printer. Enter the printer IP address in the Safari address bar, and see if a webpage shows.

There are some setup tool updates from just before Halloween, too.