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 [s@macro-auto-blkvm: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/2222@from-internal-000002a5;1 answered SIP/domain-000001f3
    [2014-06-03 12:17:28] VERBOSE[1518][C-00000075] app_dial.c: – Local/2222@from-internal-000002a5;1 answered SIP/domain-000001f3
    [2014-06-03 12:17:28] VERBOSE[1518][C-00000075] pbx.c: – Executing [s@macro-auto-blkvm:1] Set(“Local/2222@from-internal-000002a5;1”, “__MACRO_RESULT=”) in new stack
    [2014-06-03 12:17:28] VERBOSE[1518][C-00000075] pbx.c: – Executing [s@macro-auto-blkvm:1] Set(“Local/2222@from-internal-000002a5;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/1111@from-internal-000002a1;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/1111@from-internal-000002a1;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/1111@from-internal-000002a1;2’
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] pbx.c: == Spawn extension (from-internal, 1111, 22) exited non-zero on ‘Local/1111@from-internal-000002a1;2’
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] pbx.c: – Executing [h@from-internal:1] Hangup(“Local/1111@from-internal-000002a1;2”, “”) in new stack
    [2014-06-03 12:17:28] VERBOSE[1520][C-00000075] pbx.c: – Executing [h@from-internal:1] Hangup(“Local/1111@from-internal-000002a1;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.