14215: Dial->Queue: Invalid ReservationSid. Unable to dequeue

This error occurs when <Dial><Queue> receives a reservationSid that Twilio cannot use to bridge a worker to the queued caller. Use reservationSid only for calls that were enqueued with a TaskRouter WorkflowSid. When the dequeue succeeds, Twilio bridges the worker to the queued caller and marks the pending Reservation as accepted.

• The reservationSid value does not match a valid Reservation resource for the Task or Worker you are trying to dequeue. Twilio Reservation SIDs use the WR prefix.
• The Reservation was already accepted through the TaskRouter REST API or through an assignment instruction, so <Dial><Queue> cannot accept it again.
• The Reservation is no longer pending because it timed out, was canceled, was rejected, or was rescinded. Twilio can only bridge a pending Reservation with <Queue reservationSid="...">.
• The original call was not enqueued with a TaskRouter WorkflowSid, which is required before you use reservationSid on <Queue>.

• Read the ReservationSid from the TaskRouter assignment callback or retrieve the Reservation resource for the Task, then pass that exact ReservationSid value in <Queue reservationSid="...">.
• Let either <Dial><Queue> or your TaskRouter API flow accept the Reservation. Do not accept the same Reservation in both places.
• If the Reservation has timed out, return the Worker to an available Activity state and create another Task. If your application needs more time before bridging the call, increase the Workflow TaskReservationTimeout.
• Verify that you first queued the caller with a TaskRouter WorkflowSid, then bridge the worker with <Dial><Queue reservationSid="..."> only while the Reservation is still pending.

• Queueing calls with TaskRouter
• TwiML Voice: <Queue>
• Task Reservation Resource