@Kevin_Z Thanks for your answer.

I tried twice to reset to factory and configure it as range extender and it happened over the course of the past 3 days.

The guide you are mentioning below has a slightly interface than my router's one (probably it is a different model, but i have a lot less options in my left menu) and i don't find in my interface things like Enabling WDS.

Also, answering to your other points:

1. I do receive an IP as mentioned on the OP but it goes out of range . I do not receive an gateway

IP Address 169.254.245.246
DNS 255.255.0.0
Gateway empty

2. Internet connection on main router is stable. i connect to it and there are no issues. 

3. Both routers are not very far from each other, something like 10-15m. I am using WIFI 2.4GHZ and the signal intensity on the TL Router is 70%.

4. Firmware is up to date, 

Thanks

@Kevin_Z Thanks for replying.

The main router is an ASKEY RTF3505VW, provided by my ISP. So far i havent seen any strange settings. the configuration for IP, DHCP and DNSs are in the OP.

When the Router is not working, I am actually not able to access www.tplinkwifi.net, so it is not possible from my side to get a screenshot. The router shows the middle and right leds as green.

Something interesting i found is, i tried with 2 devices when the router was not working

Device A: DHCP enabled and automatic IP retrieval. Connected through an IP out of range. No internet connection

Device B: Set up manual IP connection (disable DHCP). Connects properly.

Device A: automatically gets an IP in range and internet connection is stored.

So I guess there must be some setting off and by forcing the connection through a valid IP it is restored. Do you have an idea on what the problem might be?

Thanks!