When I try to copy folders to my My Cloud, it doesn't copy all of the files

I drag folders to my My Cloud, but when I check the folders on the My Cloud, not all of the files show up. I’ve tried deleting the folder and copying it again, but the same thing happens. Sometimes none of the files copy, and the folder is only full of empty folders. How can I ensure that all of my files copy? I don’t trust my data to the My Cloud at this point.

Dragging the files to the My Cloud using what program or app on what OS or mobile device?

I’m using a Mac with the WD My Cloud app.

If your on your local network have you tried using Mac Finder to copy/drag the files?