I also have Pixma 3620. Found out that in the latest and greatest Windows 10 they have increased the strength of the firewall. Disable the Firewall and try again. The Defender may or may not be involved. Personally I use a private antivirus software and have disabled both Defender and the Firewall. Apparently someone did not include all the Canon Printers in their latest modifications. Fortunately the Canon Pixel TR4722 was included so I had a backup.To disable you have to go in and change it to a private antivirus. Then it will let you do it. But Microsoft needs to learn to be less intrusive in their security programs. That was a major goof not including all the printers many of which are models still sold as new after many years.
