Calls drop after transfer

We have an issue where sometimes when a call is transferred the call drops. I suspect that perhaps it is a NAT problem where the keep alives are not working and the firewall closes the port but I do not know how to verify this. After about 20 minutes in the log I finally found this part which shows where the call was transferred and then it hung up but could see no clues. The extension seemed to be not have been registerd (it could not be dialed) but the phone appeared to be active. Here is the log section. changed the extension numbers 2222 answered the call and tried to transfer to 1111.

  • Executing [[email protected]:8] ExecIf(“SIP/2222-000001f5”, “0?Set(MASTER_CHANNEL(CONNECTEDLINE(name))=users’s Desk)”) in new stack
    [2014-06-03 12:17:28] VERBOSE[1518][C-00000075] app_dial.c: – Local/[email protected];1 answered SIP/domain-000001f3
    [2014-06-03 12:17:28] VERBOSE[1518][C-00000075] app_dial.c: – Local/[email protected];1 answered SIP/domain-000001f3
    [2014-06-03 12:17:28] VERBOSE[1518][C-00000075] pbx.c: – Executing [[email protected]:1] Set(“Local/[email protected];1”, “__MACRO_RESULT=”) in new stack
    [2014-06-03 12:17:28] VERBOSE[1518][C-00000075] pbx.c: – Executing [[email protected]:1] Set(“Local/[email protected];1”, “__MACRO_RESULT=”) in new stack
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] app_macro.c: == Spawn extension (macro-dial, s, 7) exited non-zero on ‘Local/[email protected];2’ in macro ‘dial’
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] app_macro.c: == Spawn extension (macro-dial, s, 7) exited non-zero on ‘Local/[email protected];2’ in macro ‘dial’
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] pbx.c: == Spawn extension (from-internal, 1111, 22) exited non-zero on ‘Local/[email protected];2’
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] pbx.c: == Spawn extension (from-internal, 1111, 22) exited non-zero on ‘Local/[email protected];2’
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] pbx.c: – Executing [[email protected]:1] Hangup(“Local/[email protected];2”, “”) in new stack
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] pbx.c: – Executing [[email protected]:1] Hangup(“Local/[email protected];2”, “”) in new stack
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] pbx.c: == Spawn e

We are also having a problem with voicemail not working which may be why it hangs up. I have a separate post on that issue.