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

# Users are removed due to Personalization Failure

> Diagnose why users get removed from email campaigns due to personalization failure when custom and MoEngage-tracked attributes share the same name.

## Problem

All the users targeted via an Email campaign were removed due to personalization failure.

<img src="https://mintcdn.com/moengage/37Js42lPMANg-cwG/images/personalization-failure-email.png?fit=max&auto=format&n=37Js42lPMANg-cwG&q=85&s=6f91cc89dd8bd152c525bbe8d4273f9b" alt="Personalization Failure Email" width="1169" height="559" data-path="images/personalization-failure-email.png" />

## Cause

As the personalization was based on the custom attribute 'First Name', personalization of this campaign failed as it was looking into MoEngage tracked attribute 'First Name' because this attribute did not exist for any of the users in the target segment.

**Personalization Code: `{{UserAttribute['First Name']|default('MOE\_NOT\_SEND')}}`**

As the readable names of both the attributes i.e custom attribute 'First Name' and MoEngage Tracked attribute 'First Name' are the same, the personalization resolves to look into MoEngage tracked attribute and not the custom attribute.

## Solution

It is not recommended to track custom attributes with same names as the MoEngage tracked attributes as these are reserved keywords. Though we would be able to track this data on user profile, you would face an issue when personalization is done based on these attributes.

**List of MoEngage tracked attributes:**

```text theme={null}
1) Name
2) First Name
3) Last Name
4) Birthday
5) Gender
6) Location
7) Mobile Number (Standard)
8) Email (Standard)
9) ID
10) Advertising Identifier
```