One device allowed per house?

I had a Book Live, liked it. And bot a new My Cloud. But there seems to have conflict to have two devices in same network. I couldn’t access My Cloud from remote, while no problem with old one. 

Is that due to UPnP mapping conflict when both deivces are behind same home router?

No, that shouldn’t matter, I have a few duos, lives, and my clouds in the same network.  What does your cloud access say in the dashboard?