WAN6 interface goes down by itself

I have OpenWrt 19.07.3 r11063-85e04e9f46 on a Linksys WRT32X router.
I noticed my WAN6 interface (IPv6) sometimes goes down by itself.
Last time I tried it, after reboot the WAN6 interface came up fine, but after only 1 hour, it went down by itself.
Here is the system log. It just says

Fri Jul 24 00:05:59 2020 daemon.notice netifd: Interface 'wan6' has lost the connection

sniffe the wan packet tcpdump

I'm sorry can you elaborate what should I do? I'm not an advanced user but I can ssh to the router and run tcpdump commands.

u pc are on windows or linux ?
look at google

"wireshark windows openwrt tcpdump"

I'm on a Mac. I found this article, what does it mean "piping the data into Wireshark"? How can I view my data?

yes piping the data for seing the icmpv6 and dhcpv6 packets

I really don't know what you're talking about, so I just ran tcpdump -i eth1 (eth1 is the WAN/WAN6 interface but WAN6 is down) and this is the output:


why wan6 are down ? what is you config u use the isp router ?

Why WAN6 is down? That was my original questions... I don't know why it goes down that's why I'm here. What do you mean what is my config?

I've randomly lost ipv6/WAN_6 connection a couple of times on WRT3200ACM after disabling "Allow-ICMP-V6" via traffic rules.

Are you on a dual-stack connection via pppoe?