I have purchased an Archer C1200 to serve as an access point in my home network. I have configured the router to function in Access Point Operation Mode, but I am unable to get Internet access. I have basic networking knowledge, but am by no means an expert.

My configuration is as follows – 500 Mbps optic fiber coming into the 1^st floor of a 2-floor apartment via an ADB VV-5823 gigabit router. On the 2^nd floor, I have an Ethernet port (upstairs, on the same network) to which the Archer C1200 is connected. When I direct connect the C1200 to a port on the ADB router, I am able to get working wifi signal with Internet connectivity via the C1200. But when I connect the C1200 via the Ethernet port on the 2^nd floor I get a wifi signal, but receive the Connected, No Internet popup when trying to browse on a connected device. FYI, I have tried to configure the C1200 both with Dynamic IP and Static IP addresses.

Appreciate any/all advice and assistance.