[stumped]

see my post #13
for fire OS 6.... you probably have to select how you want the device to connect - as a media device OR for file transfer. and possibly you have to repeat that selection every time you connect. I can't give exact menus and swipe sequences as I don't have one to hand, but learnt this from connecting an android 6 phone. Fire OS 6 is mostly android 6. On the android phone its a pull down from top menu selection, and it has to be set every time, because it reverts back to being a media device

any issue with wireless trsnsfer via CC failing should be in a different thread, as that will have a different cause / solution

same applies to emailing books over. That works IF you have addresses correctly identified and whitelisted using your amazon we site pages. I would be very suprised if amazon removed the option to email a book to a device, in the latest Fire OS, but each device has its own unique amazon address for receiving email, and can only receive from addresses that are whitelisted for that device


To view or modify your Send to Kindle email address:
Go to Manage Your Content and Devices.
From Preferences, scroll down to Personal Document Settings.
Under Send-to-Kindle Email Settings, your Send to Kindle email address will be listed.
To change this email address, click Edit next to your device, enter a new email address, and then click Save to save your changes.
Note: If your device or Kindle reading app is not compatible with Kindle Personal Documents Service, a Send to Kindle email address will not be listed for that device.