I need to print on A5R paper and A7 envelopes. The printer is stuck displaying "Load Paper [1] A5R/Plain 2". The stock was correctly loaded in the paper tray, according to the reference marks inside the tray. For what it's worth, I also tried feeding an A5 sheet in the manual feed slot but this is ignored. I set the paper size in the printer "Paper Settings" menu. (It would be a little inconvenient if I need to change it back when using LTR or 8.5x11, but I understand.)
The environment is: Mac Big Sur 11.2.2, Microsoft Word 16.46 (current Mac Office 365); Canon drivers dated 3 March 2021 just updated; printer says its firmware is up to date. So as far as I can tell, everything is up to date.
I've cycled the power on the printer several times.