Is the switch connected to the router? Is the My Cloud configured for a static IP?
The My Cloud can be directly connected to a computer’s networking port, or used on a stand alone (not connected to a router) switch provided the computer is also connected to that same switch. What should happen, if the My Cloud doesn’t have a static IP, is after boot up the My Cloud should (after several minutes) display a blinking white front LED to indicate not obtaining an IP address then default to using an IP address in the 169.254.x.x range. Your computers network connection, like wise if not configured for a static IP address, should also default to using an IP address in the 169.254.x.x range when it cannot obtain an IP address. The My Cloud then should be accessible to the computer. If not try using one of the WD Access program (https://support.wdc.com/product.aspx?ID=904) that looks for the My Cloud on the local network.
If the My Cloud is configured to obtain an IP address automatically then it should pull an IP address from the router (if properly configured) if that switch is connected to a router. It is generally best to leave the My Cloud configured for default for the IP setting then access the router and assign an IP address to the My Cloud. This way the My Cloud will always use the same IP address, one that is in the same address pool as the other DHCP clients that access that router.
Connect the My Cloud to the router. Access the My Cloud Dashboard. Access the Settings > Network > Network Services section. Set Network Mode to DHCP if it is not set to DHCP already. Then access your router’s administration page and assign/reserve an IP address for the My Cloud. If you don’t know how then perform an internet search to learn how to access your router model/brand’s administration page to set or reserve a static IP address.
Or access the My Cloud Dashboard > Settings > Network > Network Services section and set Network Mode to Static and configure an IP address within the My Cloud. See the My Cloud User Manual (http://support.wdc.com/product.aspx?ID=904) or the Dashboard Help or the following WD Support document for more information on setting a static IP address.