Is Remote Access enabled (set to On) on the My Cloud? (Check the My Cloud Dashboard > Settings > General page.)
Is the office network/firewall configured to allow remote access to the My Cloud?
What program or software are you using to try and access the My Cloud remotely?
Generally one cannot access the My Cloud Dashboard remotely. By default the My Cloud blocks remote access to the Dashboard from any computer not on the local network. One can use the WD My Cloud Desktop program, the WD Sync program, the MyCloud.com web portal, and the WD My Cloud apps for Android/iOS to access a My Cloud remotely.