Here is my setup.

I have three wireless access points configured. 

Arris (cable modem)

192.168.0.1

Hitman (hardwired back to Arris)

10.65.9.1

TP-Link_Outdoor (hardwired back to Arris)

10.10.9.1

Arris and hitman have worked together for years with no issue. But recently when I added the tp-link 510 to the network it causes Arris wifi to lose internet access. 

Its strange. 

Example: I am connected to the 2.4g Arris wifi network and I am able to access the internet via this connection with no issues, everything is configured as above. I go to the mailbox and its out of range of Arris so I lose that wifi connection. I walk back to the house and I reconnect to the Arris 2.4g network but now it no longer has Internet access.  So I go to the Arris router/modem and unplug the network cable going to the CPE510 and plug it back in and I regain my access to the internet via the Arris 2.4g network. 

I also noticed via my cell phone that when I Iook at the IP that my phone pulls when its connected with no internet that the IP is that of the TP-Link network. Why would it even see the TP-Link network if its connected to the Arris network. 

IP example: When I reconnect to Arris and it has no internet I get and IP of 10.10.9.x but when I am connected to Arris with internet I get a 192.168.0.x

Why?

And what do I do to correct this. This issue does not happen with the Hitman access point at all......