If you cannot even access the My Cloud Dashboard, have you gone through the suggestions mentioned in the Compilation of Windows 10 Methods, Steps and Solutions link posted earlier? Those troubleshooting steps tend to fix many issues related to being unable to access the My Cloud assuming both the My Cloud and Windows computer are on the same local network.
In particular, from that link, look at steps Windows 10 Specific Method 1 through Windows 10 Specific Method 5 for the common things to check.
