RT-AC86u + RP-AC51 not working

[Seffy Shalem]

Hello,
I’m trying to add AC51 as extender/repeater to the AC86 existing router but without success, once I don’t with the configuration of the AC51 with the app mobile I don’t have internet access at all, not with the 86u SSID and not with the AC51 SSID.

any idea?
I see both the devices use 192.168.1.1 IP

 

[L&LD]

Make the RP-AC51 192.168.1.9 (or some other value for '9', that doesn't exist on your network's devices already) instead.