Not able to ping from LAN

You should put a better description related to the issue you are facing and the current configuration in FortiGate or FortiClient.
If you are from a remote location and are trying to connect to a VPN using FortiClient and the other side is not responding, there isn't much what you can do if you can't manage the FortiGate.

Hi Dzang

What do you mean by global IP? Is it public IP? Is it mgmt IP?

Whatever it is, keep in mind that in case the global IP is on another interface than your LAN then you need first to add a firewall rule to allow the needed traffic from your LAN to the interface where the global IP is set.

Hi @dzangpo,

Do you have PING enabled under 'Administrative Access'? Do you have trusted hosts configured? 

Regards,