This is just apocryphal / anecdotal, but there have been others with routers that have issues with Bonjour / UPnP / DLNA broadcasts that cause them to just freak out.
We see threads like this pop up on every device WD’s ever made (from the Streamers to the NASes, etc.) It often comes down to being a bug in router firmware.
Other things to look for are potentially a duplicate IP address or a bad network configuration (if done statically.)
I had some terrible issues where the MyCloud took over my port 80 forwarding which was already established to a different internal client (my web server).
This made things VERY ugly. Loss of internet access included. My router is a Cisco/Linksys E3000. The MyCloud uses UPnP but my router was not handling it correctly with port 80 already forwarded and then powering up the MyCloud.
Are you arleady fowarding 80 or 443 to a different internal host on your network? If so, try to setup on the MyCloud on DIFFERENT ports! That solved my issue.
thank you! I connected my WDmyCloud to ports 80 and 443 (which were not yet assigned elsewhere) and since then the internet didn’t crash and the connection to my WD is faster than before.