Currently one cannot “map” a remote My Cloud. Drive mapping currently only works when connected to the My Cloud on the local network. WD removed the remote drive mapping capability when they released the OS 3 firmware and revamped the WD2Go.com, now MyCloud.com web portal.
Feel free to voice your opinion of the remote drive mapping feature being removed in the following Cloud Ideas thread:
https://community.wd.com/t/re-enable-remote-drive-mapping-through-mycloud-com/134944/
If on the local network and one is having trouble with a previously mapped drive no longer working, remove the drive mapping instance and try to create a new mapped drive connection. Sometimes one has to use the IP address rather than name of the My Cloud when mapping a drive on the local network. See the following WD Support documents for more information on how to map the My Cloud.
http://support.wdc.com/KnowledgeBase/answer.aspx?ID=2676
http://support.wdc.com/KnowledgeBase/answer.aspx?ID=2686
Or see the drive mapping section in Chapter 3 in the My Cloud User Manual: http://www.wdc.com/wdproducts/library/?id=439&type=25
