The connection information screen on printer says Master1 network. When I select "Latest error information," it says "No errors."
The computer preferences>network page says Network Name: Master1. Check boxes under Network Name: "Automatically join this network" checked; "Ask to join Personal Hotspots" checked; "Limit AP Address Tracking"" unchecked; "Ask to join new networks" unchecked.
This was weird: When I was fooling around with the checkboxes under Network Name, and the "add printer" box was open elsewhere on the screen, the Canon printer suddenly showed up in the add printer box, and I selected it. While I was trying to write down what I had just done so I wouldn't forget it, the Canon printer just disappeared from the box! I can't get it back!
Again, thank you for your help.
Finally, I had a Master5 network, a duplicate I think, show up on the computer preferences networks, not selected, which I deleted. Still no printer, wah!