@kbasler on the router I have used, it is just the one selected. If you use whitelist, be sure to add the computer you are making the changes with.

@Dkay See other posts on this. You need to set the DNS in your router as it appears Apple does not think your ISP dns is safe.

@Bill00 See other posts on this. You need to change the DNS settings as it appears Apple does not think your ISP DNS is safe.

@Chuck767 Assuming the two routers have the same functions, you shoud not have much to do if you use the same settings, ssid and passwords. note the some devices may not connect and you will need to...

@M8888 If you unplug the nvr, does it start working correctly? If your nvr set up for port forwarding and is the ip address reserved?

@mmtkd By chance are you using access control using MAC addresses? If so, that may be the issue.Apple has an option to change the MAC address.