Disconnect Codes

When a call ends, the webhook payload includes a status and potentially error codes. Understanding these is vital for debugging connection issues.

SIP Response Codes

If you are using SIP Trunking (or debugging Twilio logs), you may see standard SIP codes.

Code	Meaning	Common Cause	Action
200	OK	Successful call termination.	None.
404	Not Found	The number dialed does not exist.	Check the `to_number`.
408	Request Timeout	The recipient’s phone rang but wasn’t picked up.	Retry later.
480	Temporarily Unavailable	The recipient has no signal or is in DND.	Retry later.
486	Busy Here	The recipient rejected the call or is on another line.	Retry later.
503	Service Unavailable	Carrier or Platform issue.	Check status page.
603	Decline	The recipient explicitly blocked the call.	Do not retry immediately.

These are the internal statuses you will see in the API and Dashboard.

Status	Meaning
`queued`	The call request has been accepted but hasn’t started dialing yet.
`initiated`	Dialing has begun.
`ringing`	The recipient’s phone is ringing.
`in-progress`	Connection established. The bot is listening/speaking.
`completed`	Call finished successfully (hung up by either party).
`busy`	Recipient was busy.
`no-answer`	Call timed out without an answer.
`failed`	System error (invalid number, insufficient funds, configuration error).
`canceled`	The call was canceled via API before it was answered.

Cause: The phone number is not assigned to an agent in the Butter Dashboard.
Fix: Go to Agents > Phone Numbers and link the number.

Cause: LLM or TTS provider error.
Fix: Check your stt_provider and tts_provider settings. Ensure you haven’t hit a rate limit with OpenAI or ElevenLabs.