NO JOY Incomming calls drop after x seconds

[f15radar]

I am getting my calls but after between 5-60 seconds the calls drop. Here is my log

-- Channel SIP/701-00000006 left 'simple_bridge' basic-bridge <860fdf36-d04f-4d5a-b9d8-1cfe1f1f5f78>
-- Channel SIP/Skyetel-SE-00000005 left 'simple_bridge' basic-bridge <860fdf36-d04f-4d5a-b9d8-1cfe1f1f5f78>
== Spawn extension (macro-dial-one, s, 54) exited non-zero on 'SIP/Skyetel-SE-00000005' in macro 'dial-one'
== Spawn extension (macro-exten-vm, s, 14) exited non-zero on 'SIP/Skyetel-SE-00000005' in macro 'exten-vm'
== Spawn extension (ext-local, 701, 2) exited non-zero on 'SIP/Skyetel-SE-00000005'
-- Executing [h@ext-local:1] Macro("SIP/Skyetel-SE-00000005", "hangupcall,") in new stack
-- Executing [s@macro-hangupcall:1] GotoIf("SIP/Skyetel-SE-00000005", "1?theend") in new stack
-- Goto (macro-hangupcall,s,3)
-- Executing [s@macro-hangupcall:3] ExecIf("SIP/Skyetel-SE-00000005", "0?Set(CDR(recordingfile)=)") in new stack
-- Executing [s@macro-hangupcall:4] Hangup("SIP/Skyetel-SE-00000005", "") in new stack
== Spawn extension (macro-hangupcall, s, 4) exited non-zero on 'SIP/Skyetel-SE-00000005' in macro 'hangupcall'
== Spawn extension (ext-local, h, 1) exited non-zero on 'SIP/Skyetel-SE-00000005

I want to say that my sip phone is double natted. My ISP does not give me a routed IP. My incrediblePBX box is located external. I have NAT checked, so I am not sure where to go from here. Thanks.

 

[f15radar]

More info......I am using Linphone on my phone as a client. I grabbed my ipod touch and put in all the same exact settings and it doesn't hang up. Turn the ipod off and switch back to my phone and it hangs up in less than 60 seconds. My phone is an iphone. Both are running the exact same version of Linphone. What am I missing?