I’ve been facing the same issues to for the past few months. I initially stumbled across this thread and tried allowing my NAS access to the internet as I had blocked it on the router, reformatted usb drive, wdcloud etc none of which worked.
Essentially the issue stems from one of the firmwares released this year has broken the functionality circa June this year 2017.
The only solution that’s fixed this issue for me was restoring back to a firmware version that I knew worked. Without wanting to try every iteration i.e guessing, I settled for the first v4 release this year v04.04.02-105 and it’s back to auto backing up.
However initially you will need to follow this guide and revert the firmware version to predate the version you want to update too.
Read this but substitute the new firmware to be the version I have. I tried V3, but it was not working correctly for me and lost all my content, albeit the revised v04.04.02-105 it was back as before.
