calibre to Kindle Cannot write to file error

Kindle Fire 5th Gen running Fire OS 5.3.1.0
calibre version 2.70 (64-bit)
Windows 10

Cannot write to file: hr=2147500037 facility=0 error_code=16389 description: Unspecified error


Traceback (most recent call last):
File "site-packages\calibre\gui2\device.py", line 88, in run
File "site-packages\calibre\gui2\device.py", line 506, in _books
File "site-packages\calibre\devices\mtp\driver.py", line 218, in books
File "site-packages\calibre\devices\mtp\driver.py", line 190, in get_driveinfo
File "site-packages\calibre\devices\mtp\driver.py", line 180, in _update_drive_info
File "site-packages\calibre\devices\mtp\driver.py", line 151, in put_calibre_file
File "site-packages\calibre\devices\mtp\windows\driver.py", line 37, in check_thread
File "site-packages\calibre\devices\mtp\windows\driver.py", line 441, in put_file
WPDError: Cannot write to file: hr=2147500037 facility=0 error_code=16389 description: Unspecified error

I have un/reinstalled calibre.
I have done a factory reset on the Kindle.

Why does it still continue to give me this error? The Kindle is new. The version of calibre is new. Until recently, it worked perfectly.

Any helpful advice would be greatly appreciated.