Fortigate 40F VPN from Branch to HQ only for internet

i am try ting to config 40F to 40F using site to site vpn when HQ has Static WAN ip and Branch use Dynamic , after config the tunnel is still down , even i try Hub - Spoke same issue , in HQ the 40F setup is behind the main Firewall ( 60F ) , does it required any Port forwarding . i have go through several video and documents , the config show ok ,still the VPN not coming online .