I purchased the Deco Mesh W2400 with two units. I used the app to set up and followed the instructions, successfully set up my Network and connected to both units, the main Deco connected by Ethernet cable to my modem (Arris Surfboard) that works with previous router (also TP Link). When I try to connect any device, they connect to the network but says there is no Internet. I removed the units and reconnected the old router and everything works fine. What can I do to make the mesh work before I just return it? Thanks!