*CLI> set verbose 99
Verbosity was 0 and is now 99
*CLI>     -- Registered IAX2 '123456' (UNAUTHENTICATED) at 201.27.90.194:4569
    -- Accepting UNAUTHENTICATED call from 201.27.90.194:
       > requested format = gsm,
       > requested prefs = (),
       > actual format = gsm,
       > host prefs = (),
       > priority = mine
    -- Executing Dial("IAX2/123456-3", "Zap/1/44882120") in new stack
Jun 22 01:32:32 NOTICE[10935]: app_dial.c:1040 dial_exec_full: Unable to create channel of type 'Zap' (cause 0 - Unknown)
  == Everyone is busy/congested at this time (1:0/0/1)
  == Auto fallthrough, channel 'IAX2/123456-3' status is 'CHANUNAVAIL'