Yes, my PBX has a private LAN IP- 10.0.250.60.
Settings-> Asterisk SIP Settings-> General SIP Settings
I know my network diagram shows additional networks but right now I’m just focused on getting it to work with my test network. Once I’ve found the issue, I can apply the changes accordingly for the other networks.
Settings-> Advanced Settings-> Device Settings
Since these sites are connected over a VPN, NAT should not be an issue. Calls from the Remote Sites are routing to the Main Site public IP address over the WAN connection and not the private IP address of my PBX over the VPN between the sites as I want them to. None of my phones will ever access the PBX from the public Internet so all traffic should be coming from/going out over the VPN connections (except for the traffic that needs to go to my trunk provider, obviously).