Your Canon printer offline on Mac due to various reasons such as a connection issue, a hardware problem, or a driver issue. First, make sure the printer is turned on and connected to the same network as your Mac. Check the printer queue for any stuck print jobs and clear them. Also, make sure that the printer driver is installed correctly and is up to date. You can update the printer driver from the Canon website. If the printer is still offline, try restarting your printer, Mac, and router.