A Canon printer that works on Monday and shows "Offline" on Wednesday is one of the most common home-printing complaints. In most cases the printer is still on the network. What has broken is the computer's route to it. The checks below find which part is failing, roughly in order of how often each one is the cause.
Most routers hand out addresses through DHCP, and after a power cut or router restart they can give the printer a new one. If Windows or macOS installed the printer against the old address, it keeps looking in the wrong place and reports the printer as offline. The lasting fix is a DHCP reservation in your router's settings, which ties the printer's MAC address to one fixed IP. You can print the printer's network settings page to see its current IP and MAC address. Then remove the printer from the computer and add it again. If you want the full walkthrough for Windows and Mac, this guide shows how to fix a Canon printer that keeps going offline step by step.
Many PIXMA models switch themselves off after a period of inactivity. A printer that is fully off can't answer the computer, so it shows as offline until someone presses the power button. Open the printer's settings from its menu, the Canon PRINT app, or its web page (type the IP address into a browser), and lengthen or disable Auto Power Off. Sleep mode on its own is normally fine, because the printer wakes up when a job arrives.
On Windows, open the print queue and make sure Printer > Use Printer Offline isn't ticked. Also look at the port in Printer properties. If the printer was added through a WSD port, Windows can lose track of it after network changes. Adding it again with a Standard TCP/IP port that points at the reserved IP is usually much more stable.
On a Mac, open System Settings > Printers & Scanners, remove the printer and add it again.
Most home PIXMA models only use the 2.4 GHz band. Mesh systems that combine 2.4 and 5 GHz under one network name sometimes move devices between access points, and printers handle that badly. If your router allows it, give 2.4 GHz its own name and connect the printer to that, or turn off band steering for the printer only. Placing the printer closer to the main router or a mesh node also helps if the signal is weak.
Some firewalls and router "client isolation" settings block printer discovery. Make sure the printer and the computer are on the same network, not one on the main network and the other on a guest network. A VPN on the computer can have the same effect, because it moves traffic away from the local network.
If the printer drops off and won't rejoin even after a restart, the problem is the Wi-Fi connection itself rather than the computer's route to it. Common causes are a changed router password, a new router, or a network that is 5 GHz only. In that case, start with the steps for a Canon printer not connecting to Wi-Fi, then come back and set up the IP reservation so the problem doesn't return.
Written by Abhi Y., PrinterSolved. This is an independent guide and is not affiliated with Canon Inc. For warranty or hardware faults, contact Canon support directly.