Yes, it helped me rm /overlay/upper/etc/config/firewall !!
After restoring firewall configuration issue solved !!
Seems like I am messed up with firewall settings !!
Seems like was missed some config rule because previously I did not have it in /etc/config/firewall ... (
Thank you @mk24 !!
Thanks you all for your support !!
Also one additional question, could you please suggest documentation, book or manuals for proper configuring Routers on Linux specifically ?
I know theory, but theory is different from practice, I want some good book how to configure router, switch on linux, openwrt and so on ??
OpenWRT documentation is good, but seems like I missed some basis from the practice point of view ...