# 14215: Dial->Queue: Invalid ReservationSid. Unable to dequeue Log Level: ERROR ## Description This error occurs when `` 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. ### Possible causes * 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 `` 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 * The Reservation is no longer pending because it timed out, was canceled, was rejected, or was rescinded.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 ``. * The original call was not enqueued with a TaskRouter `WorkflowSid`, which is required before you use `reservationSid` on ``. ### Possible solutions * Read the `ReservationSid` from the TaskRouter assignment callback or retrieve the Reservation resource for the Task, then pass that exact `ReservationSid` value in ``. * Let either `` 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 `` only while the Reservation is still pending. #### Additional resources * [Queueing calls with TaskRouter](/docs/taskrouter/twiml-queue-calls) * [TwiML Voice: ``](/docs/voice/twiml/queue) * [Task Reservation Resource](/docs/taskrouter/api/reservations)