I have the My cloud app to backup pictures and videos from cell phone to my cloud device. Sometimes it works and does not. I even have to log out and remove and re add device to back up
What cell phone version? iOS or Android? Have you checked the Mobile Apps subforum to see if there are other discussions that are similar to your issue? You can use the forum search feature, magnifying glass icon upper right, to search for past discussions.
https://community.wd.com/c/wd-software-mobile-apps/wd-my-cloud-3rd-party-mobile-apps
