# 14211: Dial->Queue: Invalid whisper url

Log Level: ERROR

## Description

Twilio returns this error when the `url` attribute on `<Dial><Queue>` is not a valid relative or absolute URL for the TwiML document that runs on the queued caller's leg before the calls connect.

### Possible causes

* The `<Queue>` `url` value is malformed.
* An absolute `url` is missing the protocol, hostname, file path, or properly URL-encoded query parameters.
* Twilio cannot retrieve the document from the `url` because the endpoint is not reachable or not reliably available to Twilio.

### Possible solutions

* Set the `<Dial><Queue>` `url` attribute to a valid relative or absolute URL.
* If you use an absolute `url`, include `http://` or `https://`, a hostname, a file path, and properly URL-encoded query parameters.
* Make sure Twilio can reach the endpoint over the public Internet and retrieve it reliably before the queued call is bridged.
* Return a valid TwiML document for the queued caller. Use only `Play`, `Say`, `Pause`, and `Redirect` in the document requested by the `url`.

#### Additional resources

* [TwiML Voice: `<Queue>`](/docs/voice/twiml/queue)
* [Queue Calls](/docs/voice/queue-calls)
* [Availability and Reliability](/docs/usage/security/availability-reliability)