Extensions.conf:

exten => 766,2,Goto(interno,444,1)

exten => _[4589]XX,1,Dial(IAX2/${EXTEN},30,TtrwW)
exten => _[4589]XX,2,Dial(SIP/${EXTEN},30,TtrwW)
exten => _[4589]XX,3,Voicemail(u${EXTEN})
exten => _[4589]XX,4,Playback(vm-isunavail)
exten => _[4589]XX,5,Hangup

exten => _*8.,1,Pickup(${EXTEN:2})
exten => _*8.,2,Hangup()



CLI: 


    -- Accepting call from '150' to '766' on channel 0/31, span 2
    -- Executing [766@internacional:1] Dial("Zap/62-1", "IAX2/766|20|TtrwW") in new stack
[Dec 19 13:54:58] WARNING[15762]: chan_iax2.c:2862 create_addr: No such host: 766
[Dec 19 13:54:58] WARNING[15762]: app_dial.c:1131 dial_exec_full: Unable to create channel of type 'IAX2' (cause 3 - No route to destination)
  == Everyone is busy/congested at this time (1:0/0/1)
    -- Executing [766@internacional:2] Goto("Zap/62-1", "interno|444|1") in new stack
    -- Goto (interno,444,1)
    -- Executing [444@interno:1] Dial("Zap/62-1", "IAX2/444|30|TtrwW") in new stack
    -- Called 444
    -- Call accepted by 192.168.4.119 (format alaw)
    -- Format for call is alaw
    -- IAX2/444-48 is ringing
    -- Channel 0/31, span 2 got hangup request, cause 16
    -- Hungup 'IAX2/444-48'
  == Spawn extension (interno, 444, 1) exited non-zero on 'Zap/62-1'
    -- Executing [h@interno:1] Hangup("Zap/62-1", "") in new stack
  == Spawn extension (interno, h, 1) exited non-zero on 'Zap/62-1'