# Call Reason Errors

1. **Invalid input:** The issue is with the request payload. Please check if the request body is well-formed, the key names and values are as per the API documentation. Special characters, if any, are not allowed in the call reason. For more details on special characters, refer to this [link](https://docs.truecaller.com/truecaller-for-business/features/call-reason/what-are-the-guidelines-for-call-reason).
2. **Not a Truecaller user:** The receiver is not a Truecaller user, or they might have uninstalled the app or switched to a new device that does not have Truecaller installed. 
3. **OS not supported:** User is on an operating system other than Android. Please note that personalized call reason is only available for Android devices. 
4. **App version not supported:** User is on a very old version of Android which is not supported now.
5. **Failed to push:** This is returned when system is unable to establish a connection with user's device. Reasons can include but are not limited to:
   1. Out of network zone
   2. Bad internet
   3. Airplane mode


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.truecaller.com/truecaller-for-business/verified-business-api-documentation/call-reason-errors.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.