Connecting MacBook Air to Canon Pixma MP250

Canon Support – Pixma MP250

"PIXMA MP250 has been retired. Product support is no longer available. Driver and content updates are not being made."

I do not see printer or scanner drivers for any version of macOS later than Sierra, which is probably a bad sign. The specifications say it is compatible with Mac OS X 10.3.9 to 10.5.x (which are much older even than Sierra, indicating that Canon introduced this printer a very long time ago).

The printer does not appear to support AirPrint.

About AirPrint - Apple Support

The VueScan (Hamrick) site indicates that VueScan supports the MP250, so if you purchased VueScan, you could use it to rescue the scanner part of the MP250. However, if Canon's printer drivers do not work on Big Sur and the printer does not support AirPrint, you'd only be rescuing the scanner.

Sounds like it's time to replace that MP250 with something newer that is AirPrint-compatible.

It may not work at all, but since the equipment line indicates that you are using macOS 11 Big Sur, you may want to test the Canon Printer Drivers v3.4 for macOS - Apple Support. If the package installs properly, look for something like a Canon MP250 series (16.10.0.0?) printer driver. This would be entirely experimental.

By the way, the separate (similar/same?) macOS 10.12 Sierra driver from Canon mentioned by Servant of Cats could possibly be worth testing as well.

As always, make sure that you have backup copies of all important files before testing anything. Software conflicts cannot be ruled out

Without details beyond "not working" we can only guess, but perhaps something here will help:

https://support.usa.canon.com/kb/s/article/ART165717

Regards.