-- Executing Dial("SIP/daan-b7908728", "ZAP/1/0642732216") in new stack
    -- Requested transfer capability: 0x00 - SPEECH
    -- Called 1/0642732216
Mar 18 19:03:44 WARNING[5827]: chan_zap.c:8650 zt_pri_error: 1 Write to 23 failed: Unknown error 500
Mar 18 19:03:44 WARNING[5827]: chan_zap.c:8650 zt_pri_error: 1 Short write: 0/10 (Unknown error 500)
Mar 18 19:03:44 WARNING[5827]: chan_zap.c:3972 zt_handle_event: Detected alarm on channel 1: Red Alarm
    -- Hungup 'Zap/1-1'
  == Everyone is busy/congested at this time (1:0/0/1)
  == Auto fallthrough, channel 'SIP/daan-b7908728' status is 'CHANUNAVAIL'