Hi there,
Sorry to hear about your experience. You mentioned that you are not able to copy the files from server to desktop. It looks like permission issue on server's end. Has there been any change/update in the permissions/security policies of the server?
Are you able to open this file on your end? Try any other method(any other cloud service to share your file with coworker and see if it helps?
Let us know how it goes. Looking forward to your response.
Regards,
Ashutosh