Re-add your printer from the print queue to resolve the Cannon printer offline Mac issue. Hit the icon of Spotlight and open Printers & Scanners. Tap the name of your Cannon printer and choose the Remove Printer option. Now, tap Remove Printer when the prompt appears. After that, tap Add Printer, Scanner, or Fax. Choose your Cannon printer followed by tapping the Add option. You can also restart the printer to fix the offline error.