From a windows command prompt run the following command:
arp -a
This will show all IP and Mac addresses on your lan. Then you can check using your mac address of the WD My Cloud. To see if it is listed. When you find the mac address you will also know the IP address. Put this ip address in the browser address bar and see if you connect.
What is your network layout? Is your My Cloud connected to a router? On the bottom of the MyCloud is the mac address. This is the address you need to find in the arp -a output.
My layout is modem connected to the router. PC and My Cloud connected to router.
This is what it was. High fibre network had been installed recently and there was another modem (hidden) and THIS is the modem the MyCloud should have been attached to.
Simple but annoying as I didn’t know there was another router.