Calibre error message

Hello
I am getting the following error message on starting Calibre today. I have recently uploaded the following plugins in an attempt to get Kobo books to install (DeDRM 6.5.1, Kepub Input 2.7.3, Kobo Utilities 2.4.1, and Obok DeDrm 6.3.6)

Thanks in anticipation RTW

calibre, version 2.68.0
ERROR: Error: Error communicating with device

Cannot write to file: hr=2147942721 facility=7 error_code=321 description: The device is unreachable.


Traceback (most recent call last):
File "site-packages\calibre\gui2\device.py", line 87, in run
File "site-packages\calibre\gui2\device.py", line 503, in _books
File "site-packages\calibre\devices\mtp\driver.py", line 216, in books
File "site-packages\calibre\devices\mtp\driver.py", line 188, in get_driveinfo
File "site-packages\calibre\devices\mtp\driver.py", line 178, in _update_drive_info
File "site-packages\calibre\devices\mtp\driver.py", line 149, in put_calibre_file
File "site-packages\calibre\devices\mtp\windows\driver.py", line 35, in check_thread
File "site-packages\calibre\devices\mtp\windows\driver.py", line 439, in put_file
WPDError: Cannot write to file: hr=2147942721 facility=7 error_code=321 description: The device is unreachable.