NAS not detected using Ethernet connection to Technicolor TG582n FTTC router

[#1]

Hi,
I've just switched to Plusnet and have been setting up the boxes today. One problem so far - I've got a Zxyel NSA221 NAS which previously was connected to a Netgear router via an ethernet connection which worked fine. When I connect it to the Technicolor  router using the ethernet cable supplied, the ethernet light on the router lights and flashes as does the green network light on the ethernet port on the NAS, but I can't see the NAS on my mac or PC, or in the web interface for the router - it just says no devices attached. Any ideas please?
Thanks
David

[#2]

Is the NAS set to a static IP address outside the routers subnet.

[#3]

Thanks - that seems to have done the trick. the old IP address was outside of the range. I had to allocate a static IP address - couldn't seem to get it to work using dynamic allocation. As long as it works, I'm happy.