Only cable works, there is wifi but cant access internet and modem or router

[pedroh.borgess]

Only cable connection, all devices can find and connect to the wifi but there is no internet.
Cant access the modem config over wifi, even if it is connected.
Already tried to factory reset the router, still not working.
No new device added on those days
The router is ARRIS TG2492S
the devices are a notebook (that I can connect via cable), a router using repetition mode (with a PC connected via cable that do not have internet also as the router is not connected), a galaxy S8 and some smart-plugs.
None of those devices can connect on the wif (2.4 or 5GHz), but cabled works.

 

[failboat]

Make sure there are no conflicts with the gateway. the repeater might be trying to use the same ip. unplug everything except a test device or try the repeater first.