Comment 2 for bug 1781922

That is an error communicating with the device. Usually, this kind of error can be fixed by
following the steps below in sequence. First:

        1) Try rebooting both the device and your computer
        2) If that does not work, find the files driveinfo.calibre and metadata.calibre on the device
           and delete them (you can use Windows Explorer or a file manager on the device itself to do this)
        3) Reset the device

If none of those work, you can use one of the wireless communication methods described here:
https://manual.calibre-ebook.com/faq.html#how-do-i-use-calibre-with-my-android-phone-tablet-or-kindle-fire-hd

 status invalid