> ## Documentation Index
> Fetch the complete documentation index at: https://moengage-user-guide.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Why Does Encryption or Decryption Fail in Email Campaigns?

## Problem

When sending an Email campaign during testing, the message “Users removed due to Encryption/Decryption failure” is received. Even though encryption is enabled for one attribute, it is not utilized in the campaign.

<img src="https://mintcdn.com/moengage-user-guide/9sGRfPooGTQ_AwT3/images/moengage_21f333.png?fit=max&auto=format&n=9sGRfPooGTQ_AwT3&q=85&s=36f57329fab144af81360f10a8b1feea" width="1600" height="634" data-path="images/moengage_21f333.png" />

## Solution

* This error indicates an issue with how personally identifiable information (PII) is being handled in your campaign.
* This can occur even if you have enabled the *PII Encryption* feature (**Encrypt attribute** toggle) for your workspace.
* You should pass the email data in an encrypted format to ensure the expected behavior of the *PII Encryption* feature.
* Enabling the *PII Encryption* feature (**Encrypt attribute** toggle) will automatically encrypt future email data, preventing this issue.
  <img src="https://mintcdn.com/moengage-user-guide/9ZDoUAfIV0lDtmVh/images/moengage_53a0b3.png?fit=max&auto=format&n=9ZDoUAfIV0lDtmVh&q=85&s=3e0b8d864d14bd9a5b3c0a64d782a8be" width="1600" height="811" data-path="images/moengage_53a0b3.png" />
  <Warning>
    PII data will be encrypted using server-to-server (S2S), SDK, and user import version 2. However, the user import version 1 is not supported for this purpose.
  </Warning>