# 32711: Voice User-Defined Message: Request to subscription callback URL encountered error

Log Type: APPLICATION

Log Level: WARNING

## Description

Twilio received an error response when attempting to send a User-Defined Message event to the UserDefinedMessageSubscription callback URL.

### Possible causes

* The UserDefinedMessageSubscription callback URL is incorrect.
* Your endpoint at the UserDefinedMessageSubscription callback URL was not responding or responded with a 400- or 500-level HTTP status code.

### Possible solutions

* Make sure that the UserDefinedMessageSubscription callback URL is correct.
* Make sure that your endpoint at the UserDefinedMessageSubscription callback URL can successfully receive and respond to requests with 200-level HTTP status codes.