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

# Invalid Property Error

An event triggered when the web store receives malformed or invalid data in the session or offer configuration, typically due to incorrect formatting or missing required fields.

**Event Data**

<ResponseField name="timestamp" type="number">
  The time when the event occurred. Example: `1632345000`
</ResponseField>

<ResponseField name="data" type="object">
  Details about the event failure.

  <Expandable title="properties">
    <ResponseField name="requestId" type="string">
      A unique identifier (UUID v4) for the request. Example: `550e8400-e29b-41d4-a716-446655440000`
    </ResponseField>

    <ResponseField name="playerId" type="string">
      The player ID returned during authentication. Example: `player_12345`
    </ResponseField>

    <ResponseField name="offerExternalId" type="string">
      The publisher offer ID, if applicable. Example: `offer_56789`
    </ResponseField>

    <ResponseField name="reason" type="string">
      The reason for the error in JSON stringified format. Example: `{"error": "Invalid property 'price'"}`
    </ResponseField>
  </Expandable>
</ResponseField>

<ResponseExample>
  ```json Event Payload theme={"system"}
  { 
    "timestamp": 1632345000, 
    "data": { 
      "requestId": "550e8400-e29b-41d4-a716-446655440000", 
      "playerId": "player_12345", 
      "offerExternalId": "offer_56789", 
      "reason": "{\"error\": \"Invalid property 'price'\"}" 
    } 
  }
  ```
</ResponseExample>