Restarting your printer and starting Run will fix the why is my canon printer offline problem. Select Device and Printers from the control panel at this point. Choose A green checkmark when you right-click on the symbol. Select the context menu to see what is printing. If your printer is gray, right-click on it and select Set as Default Printer from the context menu. Finally, uncheck the two boxes next to Use Canon Printer Offline and Pause Printing if you can see them by pressing the printer.