---
page_type: error
code: 21205
message: "21205: Invalid URL"
level: ERROR
---

## Error - 21205

### Invalid URL

You attempted to initiate an outbound phone call, but the URL you specified to handle the call was not a valid URL.

If you specified an Application Sid for your outbound phone call, the application must have a valid VoiceUrl or the call will fail.

#### Possible Solutions

Make sure you submit a fully qualified URL including:

- protocol (http:// or https://)
- hostname
- file path
- properly url-encoded query parameters

Twilio must be able to reach this URL over the public Internet.