I have never seen this error before, what doe s it...
# ask-air
rich-megabyte-73517
05/27/2026, 2:37 PMI have never seen this error before, what doe s it mean? the call didn’t go thru CRITICAL: AgentInitializationError in phone-worker
🚨 AgentInitializationError — phone-worker
Environment: production
From Number:
<tel:+17037312463|+17037312463><tel:+17036868627|+17036868627>9a16fbf4-2778-4718-9d96-493dd0bcc6dainbound-call-_+17037312463_33R9k5dhBre9aa0c8b37-ecae-45e9-9e97-8c1a7313328a Copy code
room error engine: connection error: engine is closed Copy code
Traceback (most recent call last):
File "/app/app/livekit_worker.py", line 2232, in entry
await agent.initialize(ctx)
File "/app/app/agents/standard_agent.py", line 674, in initialize
await self._background_audio.start(ctx.room, self.session)
File "/app/app/pipeline/audio_background.py", line 117, in start
return await self._start_ambient_mode(room, session)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/app/app/pipeline/audio_background.py", line 145, in _start_ambient_mode
await self._player.start(
File "/usr/local/lib/python3.11/site-packages/livekit/agents/voice/background_audio.py", line 262, in start
await self._publish_track()
File "/usr/local/lib/python3.11/site-packages/livekit/agents/voice/background_audio.py", line 394, in _publish_track
self.publication = await self._room.local_participant.publish_track(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/livekit/rtc/participant.py", line 759, in publish_track
raise PublishTrackError(cb.publish_track.error)
livekit.rtc.participant.PublishTrackError: room error engine: connection error: engine is closedt
tall-airline-16756
05/27/2026, 2:38 PMThanks for reaching out, luisa. I'm an AI assistant and I'm here to help. Give me a moment while I research this topic.
tall-airline-16756
05/27/2026, 2:38 PMThanks — I see you’re asking what the "AgentInitializationError in phone-worker" means for the failed call. I looked at the stack trace and room/agent info you provided.
What happened (short): the agent failed while starting background audio because the WebRTC engine for the room was already closed when it attempted to publish a track. The immediate error from the SDK is: "room error engine: connection error: engine is closed" which surfaced as a PublishTrackError and bubbled up to AgentInitializationError.
Likely causes to check next:
• The WebRTC/signaling connection closed before background audio publish completed (network flare, signaling failure, or worker restarted).
• A race where the agent tried to publish background audio before the room/engine was fully connected.
• Resource or startup delay on the worker causing the engine to time out or be closed.
Next troubleshooting steps you can try:
1. Check room lifecycle around the timestamp (May 27, 2026 142734 UTC):
◦ Was the room created and stable before the agent initialized?
◦ Any server restarts, worker crashes, or network interruptions at that time?
1. Inspect agent/worker logs for earlier connection errors or disconnect reasons for that room/agent ID (
9a16fbf4-...inbound-call-_+17037312463_33R9k5dhBre9publish_track()publish_track()