# 40139: Failed to issue Conference Instruction due to invalid ActivitySid

Log Type: APPLICATION

Log Level: ERROR

## Description

Conference Instruction requires a valid `post_work_activity_sid`

### Possible causes

* The provided `post_work_activity_sid` is invalid or no longer exists in the operating Workspace.

### Possible solutions

* Ensure that a valid ActivitySid is provided in the `post_work_activity_sid` property in the Worker's attributes or request parameters.

#### Example

```bash
{
	"instruction": "conference",
	"to": "client:alice",
	"from": "bob",
	"post_work_activity_sid": "WA0123456789abcdef0123456789abcdef"
}
```