OpenVPN Not Working with Sangoma Phone

I buy the Sangom S305 phone + Sysadmin Pro module.

I setup the OpenVPN and confirm from my laptop it connects fine and I can access the FreePBX

Then I provision the phone for OpenVPN and the VPN icon shows up at time. But I take the phone offsite and the VPN connection is not established, it shows in the menu VPN IP = 0.0.0.0

How can I view the logs of VPN on the phone? When I login to the web interface there is no mention of VPN