Help in making an old router a Wifi Repeater

Hi everyone. My device is as follows

Hostname OpenWrt
Model TP-Link Archer C20i
Architecture MediaTek MT7620A ver:2 eco:6
Firmware Version OpenWrt 21.02.1 r16325-88151b8303 / LuCI openwrt-21.02 branch git-21.295.67054-13df80d
Kernel Version 5.4.154

I have followed the instructions on this page to configure my old router as a Wifi repeater but no success. After following the steps via LuCi, when trying to connect to the OpenWrt Repeater Wifi it doesn't get an IP, instead it gets a IPV6 address and says "no internet connection".

Could anyone help please? Below are some screenshots.

The instruction works, I did it just before Christmas, both devices running 19.07.8.

I think you have to use a static IP, in the REPEATER_BRIDGE.
Make sure it matches the IP assigned by the main router, or add it to static leases in the
DHCP (of the main router), that's what I've done.