you have to make sure you have port forwarding set correctly on your router. you can often times put the device in whats called in some routers a DMZ which will allow everything to connect to it. i am sure you also have to set the nvr to connect to the site in its firmware if it hasnt already been done.
btw if you go here
http://hdcctv.co.uk/products/hd-ip-professional-9-16-camera-network-video-recorder-xrn1609
they have a video on how to set up with goolink