> ## Documentation Index
> Fetch the complete documentation index at: https://docs.inboxapp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Prevent messaging leads you’ve already contacted

> Exclude the Contacted system list in campaign settings so prior outreach isn’t duplicated.

Requires **Pro**.

Exclude the **Contacted** system list on a campaign so prior outreach isn’t duplicated. What Contacted contains: [How the Contacted list prevents duplicates](/help/leads-management/concepts/how-the-contacted-list-protects-you-from-duplicate-messaging).

## Exclude Contacted

1. Create or edit a campaign.
2. Open **Campaign Settings**.
3. Under **Excluded Lists**, select **Contacted**.
4. Save.

<Frame>
  <img src="https://mintcdn.com/inboxtechinc/dgSDSEato981ZoWO/images/help/how-to-prevent-messaging-leads-you-ve-already-contacted/image-1968428867.png?fit=max&auto=format&n=dgSDSEato981ZoWO&q=85&s=9b1c4d796352e7b421c7a2634db44c48" alt="Campaign settings showing excluded Contacted list" width="1920" height="1080" data-path="images/help/how-to-prevent-messaging-leads-you-ve-already-contacted/image-1968428867.png" />
</Frame>

At launch, Inboxapp removes excluded lists first, then filters unreachable DMs — [Reachable vs unreachable](/help/leads-management/concepts/understanding-reachable-vs-unreachable-leads).

## Related

* [How the Contacted list prevents duplicates](/help/leads-management/concepts/how-the-contacted-list-protects-you-from-duplicate-messaging)
* [Campaign not sending](/help/campaigns/fix/why-is-my-campaign-not-sending-messages)
* [Reachable vs unreachable leads](/help/leads-management/concepts/understanding-reachable-vs-unreachable-leads)

Still stuck? Contact support from the app.