16022: Conference does not exist or is completed

This error occurs when a request targets a conference that does not exist or is no longer active. Conference participant operations work only with active conferences, and a request fails when the specified ConferenceSid is not active.

• You submitted a ConferenceSid that does not belong to an active conference. Requests against a non-active conference fail.
• The conference ended before the request completed. A conference ends when the last participant leaves or when a participant with endConferenceOnExit="true" leaves.
• You tried to retrieve or update participants after the conference reached completed status. Participant resources are available only for active conferences.

• Confirm that the conference is still active before you add, retrieve, update, or remove participants. If you use FriendlyName, create the conference by adding the first participant with that name.
• Make participant requests before the conference ends. Do not reuse a completed conference for additional participant operations.
• Use statusCallback and statusCallbackEvent to watch for conference lifecycle events, including end, and stop participant actions once the conference is over.

• Conferences Participants subresource
• TwiML Voice: <Conference>