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

# Common campaign errors

> Most common errors when sending WhatsApp campaigns and how to resolve them.

When sending campaigns with WhatsApp templates, some messages may not be sent or delivered. Below we explain the most common errors and what each one means.

## The user's number is part of an experiment

<Accordion title="Failed to send message because this user's phone number is part of an experiment">
  This error occurs when the user's number is part of a **Meta experiment** related to marketing messages.

  During these experiments, some users cannot receive marketing messages, even if the number is valid.

  **What you can do:**

  * Ask the user to start the conversation by sending a message first.
  * Once the user writes, you will have **24 hours** to respond within the support window.
</Accordion>

## The message cannot be sent

<Accordion title="Message Undeliverable">
  This error indicates that WhatsApp could not send the message to the recipient.

  The most common reasons are:

  * The phone number does not have WhatsApp.
  * The user has not accepted the latest Terms of Service and Privacy Policy.
  * The user is using an old version of WhatsApp.

  **What you can do:**

  * Confirm that the number has an active WhatsApp.
  * Ask the user to update the app to the latest version.
  * Verify that the user has accepted WhatsApp's terms and policies.
</Accordion>

## Meta decided not to deliver the message

<Accordion title="This message was not delivered to maintain healthy ecosystem engagement">
  Meta may decide not to deliver a message to protect the user experience in the WhatsApp ecosystem.

  This usually happens when:

  * The user has received many marketing messages recently.
  * Meta detects that the message could affect interaction quality.

  **What you can do:**

  * Wait at least **24 hours** before attempting to send the message again.
  * Avoid sending repeated campaigns to the same user in a short time.
</Accordion>

## The user stopped receiving marketing messages

<Accordion title="Unable to deliver the message. This recipient has chosen to stop receiving marketing messages on WhatsApp from your business">
  This error appears when the user decided to stop receiving marketing messages from your company.

  When this happens:

  * You will not be able to send marketing templates to that number.
  * Campaign messages will not be delivered.

  **What you can do:**

  * Do not attempt to send campaigns to that user again.
</Accordion>

***

<Tip>
  **Recommendation to improve campaign delivery:**

  * Keep your contact database up to date.
  * Send campaigns only to users who agreed to receive communications.
  * Avoid sending too many marketing messages in a short time.
</Tip>