Using VOIP.MS internal Extension has a feature where you can setup multiples subaccounts and each has a distinct internal extension starting with 10. when subaccounts are registered to the same server then calls can be made between the subaccounts using the internal extension. We use the range 1000 - 1010 for our extensions. These work flawlessly when users setup a sub account using softphone such as Zoiper. Call between clients is easy, and free.

But when I try to call my FreePBX, which registers its trunk using a subccount with extension 1000, from any of the zoiper clients, it doesn’t connect.

Does anyone have words of wisdom?

I am using FreePBX 13.0.98 and used the FreePBX ISO distribution


@CharlesG How is the call being sent to the PBX and how is the PBX handling the call when it comes into the PBX?

I was using IAX and doing nothing special. But last night I switched to SIP and tada! All the problems disappeared. I can also call out to the extensions by adding 10XX as an allowed dial plan.