Hello. Have successfully set up external extensions to 3CX h/o (each on their own VPN – lan to lan) that work completely with audio, functionality, etc. when talking with extensions on the h/o lan. However, when two external extensions talk to each other e.g. external>3cx at h/o>external, there is no audio between them. Firewall settings must be fine as the external>h/o extension all works fine. Any ideas? Thank you.