The single bay My Cloud does not officially support backing up to a remote LAN. It only officially supports backing up to other locations on the local LAN.
There are several methods, using SSH where one might be able to configure the My Cloud for backup to a remote location but it is not officially supported. Do a forum search and you’ll find several threads discussing attempting remote backup. Note most of those thread deal with the older v4.x firmware My Cloud’s which are different then the newer v2.x My Clouds. Here are just two prior threads:
https://community.wd.com/t/help-new-customer-keeping-the-drive-at-another-location/161354
https://community.wd.com/t/automatic-backup-files-and-distant-bakcup/160633
