# CMP-SAMPLE-DUP — Sample messages must not be duplicates

> Sample messages must be materially different from one another.

- **Rule ID:** CMP-SAMPLE-DUP
- **Layer:** Campaign (`CAMPAIGN`)
- **Checks:** `campaign.sample[]`
- **Severity:** HIGH — Rejected by at least one carrier or provider, and a common cause of failure at the rest.
- **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:** Twilio, TCR
- **Applies:** Applies to every 10DLC registration.
- **Canonical URL:** https://ekas.io/rules/10dlc/campaign/cmp-sample-dup/

## Why this rule exists

Identical samples pad a field count without showing a reviewer anything about the program. This catches the exact-duplicate case cheaply in code; the harder question of whether two differently-worded samples are materially different is judged separately by MSG-SAMPLES-DISTINCT.

## How to fix it

Replace duplicated samples with genuinely different messages the campaign will send.

## Example of a compliant value

```text
Each sample should describe a different scenario: a promotion, an order update, an event.
```