Newbe zaptel issue

I’ve just built my second Asterisk box, This one has a digium tdm400 card in it. I’ve got 3 outgoing phone lines and a fax machine on it. Also I have 3 D-Link DPH-140S sip phones, and 2 X-Lite softphones using sip. The problem that I’m running into is that when placing outgoing calls, using any of the three lines (Goes through the list until it finds a line not in use), I get a message over the phone that says that the call can not be completed as dialed, this is an intermittent problem, and if I use redail and try again, there’s a 50-50 chance that it will go through. All inbound calls are working without fail, going through our IVR, and sending back out over the third trunk to our cell phones. I figure it’s something stupid but I’m not sure where to look.

posting your outbound context from extensions.conf and your zapata.conf would be a good start.