I realized that the pokemon GO does not work by the router
and research saw that disabling ipv6 the application was working again!
option disable_ipv6 '1'
Congratulations for the LEDE project
I really like this project
TP-Link TL-WDR3500 v1
LEDE Reboot 17.01.2 r3435-65eec8bd5f / LuCI lede-17.01 branch (git-17.152.82987-7f6fc16)
You've just disabled the IPv6 firewall rules using this option (https://lede-project.org/docs/user-guide/firewall_configuration).
Maybe you need to punch holes in your firewall, not disabling it's rules. Just a guess.
Make sure to disable the IP6 DHCP server on the LAN. For some reason it is on by default, which will cause problems in an IP4 only setup.
Pokemon is a buggy app that kind of works when only it wants to anyway. It's not necessarily your network. It should work with a default setup with no holes in the firewall.