Do you encounter this issue over WiFI, mobile data, or both? And have you tried removing permissions for the WD My Cloud application in your WD My Book Live unit, uninstalling the application, restarting your Apple-branded mobile device, and proceeding to install and re-create the permissions once more?
By “removing permissions” I mean deleting the previous access settings for your iPad from within the Dashboard configuration page of your WD My Book Live unit.
Also, even though your iPad may not have a data plan, if your phone does and it has an option for Wifi broadcasts, then it would force your iPad to connected with your phone’s data plan for testing. This option is present in most modern Android phones.