It would help if you could elaborate about the failure to scan and your Canon's model number. Does you Mac fail to connect to the scanner when you click on the Open Scanner button? Is it on your wireless network or are you using a USB cable?
If the scanner "no longer works" with the Mac then it was working earlier. Did you have any update to the system before you noticed the failure?
Is the Canon also a printer? Can you print successfully to it?
A family member with an M1 MacBook Pro (and Big Sur) noticed that her Mac ceased to connect to our wireless Canon TS8360 printer/scanner. I solved her problem by turning IPV6 to Automatic, rather than On. This setting may have turned to On by a system update. I couldn't diagnose why it was put to the On setting, but it was at Automatic at an earlier time.
You will find this at: System Preferences > Network > Advanced > TCP/IP > Configure IPV6: Automatically