Common Personalization Errors and FAQs

Personalization failure occurs when you use a user attribute or event attribute that is not present in the MoEngage dataset and do not configure a fallback.

Personalization Errors

You can see personalization errors in the Failed to Send error category in the Error breakdown table. Click See breakdown in the Name column for personalization errors to get a detailed view of the number of users for whom personalization has failed and the reasons for failure.

If you configure custom Jinja errors using the MOE_NOT_SEND tag, the error breakdown section on the campaign’s analytics page displays your specific message whenever a defined delivery condition is failed.

Personalization Failure Analysis

The Personalization failure analysis helps you identify specific attributes that cause personalization failures and offers in-depth insights into these causes.
Personalization errors can be classified into the following categories:


Error Category	Description
User Attribute	This denotes the unavailability of the user attribute used in personalization because it is unavailable in the system (for example, copy-paste errors) or for a specific user. For example, if the first_name user attribute is used in personalization and unavailable for a user, this will result in a User Attribute error.
Event Attribute	This denotes the unavailability of the user attribute used in personalization because it is unavailable in the system (for example, copy-paste errors) or for a specific user. For example, if the product_name event attribute is used in personalization and unavailable for a user, this will result in an Event Attribute error.
Campaign Attribute	This denotes an unavailability of campaign-specific information used in personalization. For example, if campaign tags are used for personalization and a campaign tag attribute is missing, this will result in a Campaign Attribute error.
Undefined	This denotes errors that happen when MoEngage cannot fetch the value for the attribute used in personalization. For example, if the image attribute is unavailable for a specific product in a product set, this will result in an Undefined error.
Unknown	This denotes any error that does not fall into the abovementioned categories.
Custom Error Message	This uses the MOE_NOT_SEND Jinja tag to define a specific reason for delivery failure when content personalization conditions are not met. This provides explicit insight into why targeted users did not receive the message due to data or attribute issues.

The number of failures listed in the Personalization Failed category under Failed to Send denotes the unique number of users for whom personalization has failed. In some cases, this might differ from the count shown in the Personalization failure analysis pop-up window, as multiple failures can happen for the same user and might be counted under each failure category shown in the UI. For example, if a user were to have a user attribute and event attribute failure, they would be counted for the number of failures in both these sections in the analysis page. In contrast, they would be counted as one in the Personalization Failed section.

Personalization Failure

Consider a scenario where you have personalized both the template and backup notifications but not added the personalization fallback. In this situation, if the personalization fails for the template or backup, the notification will not be sent to any users. This is because the template and backup are considered to be part of one payload. Because the personalization fallback does not exist, MoEngage won’t have any alternate message to send to the user in case of failure. To avoid this issue, make sure that you add a personalization backup to your messages.

Internal Errors

MoEngage internal system generates a few errors, which apply to Push messages sent to all platforms.

Error	Description
Personalization Failed	This occurs when Push Personalization fails, and you have not configured a fallback message. MoEngage will not notify the user and will generate the Personalization Failed error.

Jinja and HTML Editor FAQs

Why does my dynamically generated table render incorrectly after saving?

HTML tables have a strict structural hierarchy: <table> > <tbody> > <tr> > <td>. If a Jinja for loop is placed directly inside <table> or <tbody> — instead of wrapping a complete <tr>...</tr> row — the email HTML editor treats this as invalid markup and auto-corrects it by relocating or removing the Jinja tags when the template is saved. This is why the Jinja can look different in the backend after saving, and why the resulting table doesn’t render as expected — the editor isn’t corrupting your personalization, it’s “fixing” HTML it considers invalid. Correct pattern: wrap the entire <tr> row (not just the cell content) inside the loop, and place the loop inside <tbody>:

<table>
  <tbody>
    {% for product in products %}
    <tr>
      <td>{{ product.name }}</td>
      <td>{{ product.price }}</td>
    </tr>
    {% endfor %}
  </tbody>
</table>

Do not place {% for %} / {% endfor %} tags directly inside <table> or <tbody> without a complete <tr>...</tr> row wrapping them. The editor will relocate or strip tags placed in invalid positions, which can silently break dynamic tables.

For more information on loops, refer to Jinja Templating Language.

Why does my Jinja condition display a TemplateSyntaxError in the rich editor?

The rich (Froala) editor used for stylized email and push templates HTML-encodes the > and < comparison operators when they appear inside Jinja (> becomes >, < becomes <). This produces a template error similar to:

TemplateSyntaxError in jinja: unexpected char u'&'

and the personalization fails to render. This only affects templates authored through the rich/stylized editor. The same Jinja works correctly on a basic (non-rich) editor or in a custom HTML/source view, since there’s no encoding step involved. To avoid this:

Rewrite the condition to avoid > / < — for example, use != instead:

{# Avoid #}
{% if UserAttribute['orders']|int > 0 %}

{# Use instead #}
{% if UserAttribute['orders']|int != 0 %}

Or author the Jinja in the custom HTML/source view instead of the rich editor, where no auto-encoding is applied.

​Personalization Errors

​Personalization Failure Analysis

​Personalization Failure

​Internal Errors

​Jinja and HTML Editor FAQs

​Why does my dynamically generated table render incorrectly after saving?

​Why does my Jinja condition display a TemplateSyntaxError in the rich editor?

Personalization Errors

Personalization Failure Analysis

Personalization Failure

Internal Errors

Jinja and HTML Editor FAQs

Why does my dynamically generated table render incorrectly after saving?

Why does my Jinja condition display a TemplateSyntaxError in the rich editor?