Push notification not working with fortinet firewall 60D

Hello PBX Forum!
I am trying to setup my pbx behind fortinet 60D firewall my public IP is assigned to firwall directly as a gateway and pbx installed on local ip that is assigned by gateway lan (192.168.x.x) i am also setting up 1 to 1 natting from external ip to internal and it is working fine both side the problem is related to push notification server when i close soft phone app VitalPBX Mobile it doesn’t get register as push server as soon i reopen my soft client it gets re register with internal ip as i am testing remotely through my firewall vpn. There is two possibilities might be push server needs to be port forward to internal pbx server from external
or push server ip needs to allow in gateway firewall setting to communicate internal pbx ip
Any body who could help me regarding this issue i will be really thankful i have wasted my whole week for this task