---
page_type: error
code: 32223
message: >-
  32223: There is no username in the SIP URI when calling a SIP registered
  endpoint
level: ERROR
product: Programmable Voice
---

## Description

Calling Twilio SIP domains such as "yourdomain.sip.twilio.com" is not allowed. You can only call a registered SIP endpoint such as "username@yourdomain.sip.twilio.com".

### Possible Causes

- Attempting to place a call from Twilio back to your own Twilio SIP domain. Twilio does not allow SIP calls between Twilio domains either in the same account or different accounts.
- Attempting to call a registered SIP AOR without specifying the username you wanted to call

### Possible Solutions

- Add the correct username in the SIP URI you call, e.g., username@yourdomain.sip.twilio.com