Running Big Sur on Mac Pro. Out of the blue, printer works fine (AirPrint mode), but when attempting to now scan, I receive the message: "Failed to open a connection to the device (-21345). Printer is recognized as default printer in Printers and Scanners and no errors appear. I cannot find anything online about this error now appearing. (Firewall is disabled as well.) Printer/Scanner is a TR 7020.
I, too, have this problem. I am on an iMac, running macOS Monterey, Version 12.2.1
My printer/scanner is a Maxify GX7020, and I have only just installed it. It prints fine.
But when I try to "Open Scanner" from the OS System Preferences "Printers & Scanners", it brings up a window that initially says "Waiting for scanner...", but then, after some time, says "Failed to open a connection to the device (-21345)"
I also tried using the Canon IJ Scan Utility Lite app, and click on the "Refresh Scanner Information". It already has a Canon G7000 series entry for another Canon printer we have, but it does not find the GX7020.
Please help! It would be nice to be able to use this scanner.
Disabling IPv6 on your MAXIFY GX7020 will resolve the scanning error (-21345) that you are experiencing. To do this, please follow the steps in this article:
Disabling IPv6 on your PIXMA TR7020 will resolve this issue. To do this, please follow the steps in this article:
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We appreciate your participation, though we need to let you know that your PIXMA TS3440 appears to be a model that is not supported by our team here at Canon USA. The Canon Community Forum is hosted and moderated within the United States by Canon USA. We are only able to provide support for Canon products manufactured for and used within the US market.
If you live outside the United States, please click HERE and select your country to find support in your part of the world.
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I just got a new laptop, a MacBook Air 2020 running OS 13, and I am having the same problem. The printing works, but the scanner says "Failed to open a connection to the device (-21345). Also, I have a different printer than you. I'm having this problem with the Pixma MG3222. I logged into the IP address and disabled ipv6, but it still doesn't work.
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