It looks like calibre is failing to connect to the internet. One possible reason is because an antivirus is being overly protective.
Try excluding calibre from your antivirus.
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Sorry to hear you are having problems with calibre + Win10 + Kindle.
A number of people have reported the same problem -- the curse of the Windows 10 upgrade. For some reason, Windows is not telling applications that your ereader is a removable drive, so calibre cannot find it to connect to it.
Only in-place upgrades sem to be affected, reinstalling Windows from scratch *should* fix it.
Or you can use Connect-to-folder instead -- it needs to be done manually, but you can connect to any folder and have calibre treat it like a generic device, send books to it, etc.