Your Canon printer may show as "offline" due to several reasons, including a loose or disconnected USB cable, network issues, or incorrect printer settings. Other causes can be outdated printer drivers, print queue problems, or the printer being set to offline mode manually. To fix this, try restarting the printer and computer, checking the connection, setting the printer back online,... https://medium.com/@rashasavvy22/how-do-i-get-my-canon-printer-back-online-63e923ad947b