---
page_type: error
code: 40140
message: "40140: Failed to issue Dequeue instruction due to missing 'call_sid' property"
level: ERROR
product: TaskRouter
---

## Description

### Possible Causes

- The Task was not created via the `<Enqueue>` verb
- The `call_sid` property is missing in the Task's attributes

### Possible Solutions

- Only issue Dequeue instruction on Tasks created via the `<Enqueue>` verb
- Ensure that `call_sid` property is present in the Task's attributes