I had been unable to call landlines for some strange reason. It was in the US Virgin Islands. My trunk provider is voip.ms. Kept getting a busy signal. I troubleshooted it with voip.ms and as always they found a way.

Very simple put, my caller ID was set to area code + number. 3407741340. This caller ID worked great for any US numbers that I tried and even my 340 cellphone. I had another system setup where I was also able to call landlines. This had me believe the problem was in my dialplans. Nope, I was wrong again. If I moved the trunk out of my asterisk system and used it as a stand alone SIP trunk I had the same issue.

The solution was very simple and something I hadn’t considered. I was missing a “1” in front of the phone number listed in the caller ID. That’s it. That is all it was..