-- Executing Answer("IAX2/teliax@teliax-4", "") in new stack
    -- Executing SetGroup("IAX2/teliax@teliax-4", "test") in new stack
    -- Executing CheckGroup("IAX2/teliax@teliax-4", "0") in new stack
  == Spawn extension (from-teliax, 866xxxxxxx, 3) exited non-zero on 'IAX2/teliax@teliax-4'

extentions.conf:
exten => 866XXXXXXX/_416XXXXXXX,1,Answer()
exten => 866XXXXXXX/_416XXXXXXX,2,SetGroup(test)
exten => 866XXXXXXX/_416XXXXXXX,3,CheckGroup(0)
exten => 866XXXXXXX/_416XXXXXXX,4,Dial(IAX2/netxero@netxero/2424,20,Tr)
exten => 866XXXXXXX/_416XXXXXXX,103,Playback(tt-allbusy)