# 40142: Conference instruction failed: missing 'call\_sid' or 'outbound\_to'

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when you issue a TaskRouter `conference` instruction for a voice task that is missing the call attributes TaskRouter needs to connect the worker and caller. For inbound voice tasks created through `<Enqueue>`, accept the Reservation with `conference` to bridge the worker into a conference with the inbound caller. If you create a voice task manually and want to use `conference`, include at least `call_sid` and `to` in the Task attributes. For outbound voice tasks, include `outbound_to` in the Task attributes.

### Possible causes

* The Task was not created through `<Enqueue>` for an inbound voice call.
* The Task attributes do not include `call_sid` for the voice task.
* The Task attributes do not include `outbound_to` for the outbound voice task.
* The Task was created manually for a voice flow and does not include the minimum attributes required to use `conference`, such as `call_sid` and `to`.

### Possible solutions

* For inbound voice routing, create the Task through `<Enqueue>` before accepting the Reservation with `conference`.
* Review the Task attributes before you issue `conference`. Add `call_sid` for inbound voice tasks.
* For outbound voice tasks, add `outbound_to` to the Task attributes before you issue `conference`.
* If you create voice tasks manually, include at least `call_sid` and `to` in the Task attributes so TaskRouter can execute the `conference` instruction.

#### Additional resources

* [Task Reservation Resource](/docs/taskrouter/api/reservations)
* [How TaskRouter Works](/docs/taskrouter/how-taskrouter-works)
* [Call Control Concepts](/docs/taskrouter/contact-center-blueprint/call-control-concepts)