If you are in my canon printer is offline state and you are unable to complete the scheduled tasks then we are here to help you. This might happen if your printer is not connected to the power source but most of us overlook this because it is way too basic.
Your initial step must be to check the connection between the printer and the power source and see if there are any loose wires.
If it is connected properly then you can open the control panel to see if the canon printer is set as the default printer or not.
If you have a couple of printers connected and some other printer is set as default then your canon printer will show offline. You can disconnect the other printers and try again.