Plex wont read NAS

Im with dodo and just upgraded router. Plugged new router in. put in leads from nas and other devices no problem . Windows 10 PC still reads NAS and can play movies no problem . However when I log into plex and try and play movie, just says unavailable and cant find.
Can anyone help, and if I need to do something can u explain in laymans term, much appreciated, Thanx.

You should check how you have configured the network drive to your NAS in the Shield.
Does your NAS maybe have a new IP address and you hard-coded that in the Shield?

I will have to ask someone because honestly i have no idea about hard coding or shields.
total newbie, sorry.

Make sure you mount the nas in storage option on the nvidia shield menu