# 21767: Subscriber Out-In Missing

Log Type: TWILIO

Log Level: ERROR

## Description

The campaign submission could not be processed because an `opt_in_sample_message` was provided but `subscriber_opt_in_required` was not set to `true`

### Possible causes

`subscriber_opt_in_required` was not set to `true`

### Possible solutions

Set `subscriber_opt_in_required` as `true`