Figured it out, it seems the problem is not the Archer c80. My server running on Virtualbox using bridge network, I see someone trying to achieve that,...

Ivaylo wrote @Zuirieg It appears that you have a double NAT in your network - both devices are configured in router mode - is that right ? It would be simpler for you to manage and troubleshoot...

Port forwarding not working, I just set up my router to use Static Wan to connect to the other router. I can access the internet, but the port forwarding from ISP router to my Archer c80 not working....