SSH Access from Wan not Working

Dear Experts,

After Spending Hours i have not been able to access Asterisk from my Public IP. This Server is installed in my LAN 172.x.x.x Behind my firewall. Only My WanIP can do the HTTPs and SSH. i have changed the port of ASterisk /etc/ssh/sshd_config and i can access it via LAN. any comments will be appreciable.

Have you configured the NAT, can you check the logs of FW or monitor external access to see what happens. Can you share the logs ?