Using 2nd eth port Cap AC

Hello
I´ve got a Cap AC and a Cap lite wifi routers. I have connected the Cap AC to a fiber Router, and its wifi is working ok.
Now I need wifi in other room, so I have configured the Cap lite connecting it to the fiber Router, and its wifi is working ok too.
But now, when I connect this Cap lite to the 2nd ETH port of the Cap AC, it boots (lights are ok), I connect to its 2.4Ghz wifi, but it doesn´t assign me any IP, so all devices I connect to the Cap lite doesn´t have internet.
What must I do?
Thank you very much

Most likely you did not configure eth2 on cap ac to communicate properly with cap lite.

Easiest way to solve would be to put all eth-ports of cap ac in bridge.
To be sure, it’s best we have a look at your config of cap ac:

/export hide-sensitive file=anynameyouwish
Review export for remaining sensitive info (serial number, keys, …) and post here between [__code] quotes.