-- Executing Dial("SIP/main-5535", "zap/g1/4422713") in new stack
    -- Called g1/4422713
    -- Zap/1-1 answered SIP/main-5535
    -- Hungup 'Zap/1-1'
  == Spawn extension (to-pstn, 4422713, 1) exited non-zero on 'SIP/main-5535'