Elastix+SIP номер, проходят не все звонки

Проблема: периодически не проходят звонки на один из внешних SIP номеров. (5 пройдут 1 не пройдет или несколько минут могут не проходить, а потом опять работать без проблем)

Что имеем: Elastix 2.4.0-9, 4 городских номера по SIP. Входящие идут в IVR, а далее к секретарю. Проблема только с одним.

Настройки транка: PEER Details

username=73xxxxxxxxxx
type=peer
secret=xxxxxxxxxx
qualify=yes
nat=force_rport,comedia
language=ru
insecure=invite
host=sbc.synterra-ural.ru&tumen.synterra-ural.ru
fromuser=73xxxxxxxxx
fromdomain=tumen.synterra-ural.ru
dtmfmode=auto
disallow=all
canreinvite=no
allow=alaw

Часть лога астериска при звонке

  ...
    -- Executing [s@macro-dialout-trunk:13] Set("SIP/309-000007d0", "OUTNUM=73XXXXXXXXX") in new stack
    -- Executing [s@macro-dialout-trunk:14] Set("SIP/309-000007d0", "custom=SIP/mtt_out") in new stack
    -- Executing [s@macro-dialout-trunk:15] ExecIf("SIP/309-000007d0", "0?Set(DIAL_TRUNK_OPTIONS=M(setmusic^default))") in new stack
    -- Executing [s@macro-dialout-trunk:16] Macro("SIP/309-000007d0", "dialout-trunk-predial-hook,") in new stack
    -- Executing [s@macro-dialout-trunk-predial-hook:1] MacroExit("SIP/309-000007d0", "") in new stack
    -- Executing [s@macro-dialout-trunk:17] GotoIf("SIP/309-000007d0", "0?bypass,1") in new stack
    -- Executing [s@macro-dialout-trunk:18] GotoIf("SIP/309-000007d0", "0?customtrunk") in new stack
    -- Executing [s@macro-dialout-trunk:19] Dial("SIP/309-000007d0", "SIP/mtt_out/73XXXXXXXXX,300,") in new stack
  == Using SIP RTP TOS bits 184
  == Using SIP RTP CoS mark 5
    -- Called SIP/mtt_out/73XXXXXXXXX
    -- SIP/mtt_out-000007d1 is making progress passing it to SIP/309-000007d0
  == Spawn extension (macro-dialout-trunk, s, 19) exited non-zero on 'SIP/309-000007d0' in macro 'dialout-trunk'
  == Spawn extension (from-internal, 83452565425, 7) exited non-zero on 'SIP/309-000007d0'
    -- Executing [h@from-internal:1] Macro("SIP/309-000007d0", "hangupcall") in new stack
    -- Executing [s@macro-hangupcall:1] GotoIf("SIP/309-000007d0", "0?endmixmoncheck") in new stack
    -- Executing [s@macro-hangupcall:2] Set("SIP/309-000007d0", "MIXMON_CALLFILENAME=/var/spool/asterisk/monitor/OUT309-20160901-233815-1472751495.2288.wav") in new stack
    -- Executing [s@macro-hangupcall:3] GotoIf("SIP/309-000007d0", "1?defaultmixmondir") in new stack
    -- Goto (macro-hangupcall,s,5)
    -- Executing [s@macro-hangupcall:5] System("SIP/309-000007d0", "test -e /var/spool/asterisk/monitor/OUT309-20160901-233815-1472751495.2288.wav") in new stack
    -- Executing [s@macro-hangupcall:6] NoOp("SIP/309-000007d0", "SYSTEMSTATUS = SUCCESS") in new stack
    -- Executing [s@macro-hangupcall:7] GotoIf("SIP/309-000007d0", "1?endmixmoncheck") in new stack
    -- Goto (macro-hangupcall,s,9)
    -- Executing [s@macro-hangupcall:9] NoOp("SIP/309-000007d0", "End of MIXMON check") in new stack
    -- Executing [s@macro-hangupcall:10] GotoIf("SIP/309-000007d0", "1?nomeetmemon") in new stack
    -- Goto (macro-hangupcall,s,28)
    -- Executing [s@macro-hangupcall:28] NoOp("SIP/309-000007d0", "End of MEETME check") in new stack
    -- Executing [s@macro-hangupcall:29] GotoIf("SIP/309-000007d0", "1?noautomon") in new stack
    -- Goto (macro-hangupcall,s,34)
    -- Executing [s@macro-hangupcall:34] NoOp("SIP/309-000007d0", "TOUCH_MONITOR_OUTPUT=") in new stack
    -- Executing [s@macro-hangupcall:35] GotoIf("SIP/309-000007d0", "1?noautomon2") in new stack
    -- Goto (macro-hangupcall,s,41)
    -- Executing [s@macro-hangupcall:41] NoOp("SIP/309-000007d0", "MONITOR_FILENAME=") in new stack
    -- Executing [s@macro-hangupcall:42] GotoIf("SIP/309-000007d0", "1?skiprg") in new stack
    -- Goto (macro-hangupcall,s,45)
    -- Executing [s@macro-hangupcall:45] GotoIf("SIP/309-000007d0", "1?skipblkvm") in new stack
    -- Goto (macro-hangupcall,s,48)
    -- Executing [s@macro-hangupcall:48] GotoIf("SIP/309-000007d0", "1?theend") in new stack
    -- Goto (macro-hangupcall,s,50)
    -- Executing [s@macro-hangupcall:50] AGI("SIP/309-000007d0", "hangup.agi") in new stack
    -- Launched AGI Script /var/lib/asterisk/agi-bin/hangup.agi
    -- <SIP/309-000007d0>AGI Script hangup.agi completed, returning 0
    -- Executing [s@macro-hangupcall:51] Hangup("SIP/309-000007d0", "") in new stack