# MSG-011 — Opt-out confirmation must be 20–255 characters

> The STOP confirmation must be at least 20 and at most 255 characters.

- **Rule ID:** MSG-011
- **Layer:** Message content (`MESSAGE_CONTENT`)
- **Checks:** `campaign.optout_message`
- **Severity:** BLOCKING — Breaking this rule gets the submission rejected outright.
- **When it bites:** Gates approval — get this wrong and registration is refused
- **How it is detected:** Deterministic (settled in code from the submitted values)
- **Fix type:** Fix the field — a better value in the form clears it
- **Required by:** TCR, Twilio, Bird, Sinch
- **Applies:** Applies to every 10DLC registration.
- **Canonical URL:** https://ekas.io/rules/10dlc/message-content/msg-011/

## Why this rule exists

This is the last message you are permitted to send, so it must fit in one segment and say everything it needs to in one pass. A truncated opt-out confirmation can lose the acknowledgement itself, leaving the consumer unsure whether the unsubscribe worked.

## How to fix it

Fit the confirmation into 255 characters: brand name, the acknowledgement, and that no further messages will be sent.

## Example of a compliant value

```text
Acme Coffee: you have been unsubscribed and will receive no further messages. Reply HELP for help.
```