---
page_type: error
code: 13802
message: "13802: Dial: No referUrl attribute specified"
level: ERROR
product: Programmable Voice
---

## Description

In order to send a SIP REFER message to an established `<Dial>` call, the `referUrl` attribute must be specified in the TwiML. In this case, a REFER was received on a `<Dial>` call without a `referUrl` attribute present.

### Possible Causes

- Your `<Dial>` verb did not include a `referUrl` attribute or the attribute was misspelled

### Possible Solutions

- Add a valid `referUrl` attribute to your `<Dial>` verb
- For more information on sending REFER to Twilio, see [Refer to Twilio](/docs/voice/api/refer-to-twilio)