WRT1200AC Internet connection stopped working

I woke up this morning and my router, a Linksys WRT1200AC with the firmware version "OpenWrt 19.07.1 r10911-c155900f66 / LuCI openwrt-19.07 branch git-20.029.45734-adbbd5c" didn't have a internet connection anymore. This happened before, back then I'm not sure what I did but I reset it a couple of times and restored the backup and suddenly it started working again so I didn't want to touch it until it breaks down again.

My setup is that I get Internet into the house via fiber and then I connect that cable to the yellow "Internet" socket with a ethernet cable. When I connect my laptop to it the laptop just gets a public IP address via DHCP and I can surf, but the router doesn't.

When I use ping in Diagnostics I get the error "ping: bad address 'openwrt.org'"

Traceroute from the command line gives me:

traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 38 byte packets
 1traceroute: sendto: Network unreachable

The WAN Interface (connected to br-wan6) doesn't get any IP address and RX shows RX: 328 B (1 Pkts.)

@jeena, welcome to the community!

Are you sure that the ISP doesn't lockout the Ethernet port to MAC address X for Y period of time?

I know my FTTH ISP provider does (if I send a Client ID to the ONT).

That doesn't look good.

Please copy the output of the following commands and post it here using the "Preformatted text </> " button:
grafik
Remember to redact passwords, MAC addresses and any public IP addresses you may have

uci export network; uci export wireless; \
uci export dhcp; uci export firewall; \
head -n -0 /etc/firewall.user; \
iptables-save -c; ip6tables-save -c; \
ip -4 addr ; ip -4 ro li tab all ; ip -4 ru; \
ip -6 addr ; ip -6 ro li tab all ; ip -6 ru; \
ls -l  /etc/resolv.* /tmp/resolv.*; head -n -0 /etc/resolv.* /tmp/resolv.*