# 32223: There is no username in the SIP URI when calling a SIP registered endpoint

Log Type: APPLICATION

Log Level: ERROR

## Description

Twilio only routes a call to a registered SIP endpoint when you use the endpoint's full Address of Record, such as `username@yourdomain.sip.twilio.com`. Calling the SIP Domain by itself, such as `yourdomain.sip.twilio.com`, is not supported for this call flow.

### Possible causes

* You attempted to call a registered SIP endpoint without the username portion of the SIP URI.
* You used the SIP Domain by itself instead of the full registered endpoint AOR, such as `username@yourdomain.sip.twilio.com`.
* You attempted to place a SIP call from Twilio to a Twilio SIP Domain instead of to a registered SIP endpoint. Twilio does not allow SIP calls between Twilio SIP Domains.

### Possible solutions

* Update the destination SIP URI to include the registered endpoint username, such as `username@yourdomain.sip.twilio.com`.
* Verify that the username matches the credential configured for SIP Registration on that SIP Domain.
* If you are placing the call with the REST API or with `<Dial><Sip>`, pass the full SIP URI for the registered endpoint instead of the bare domain.

#### Additional resources

* [SIP Registration](/docs/voice/api/sip-registration)
* [Outbound - Receiving SIP from Twilio](/docs/voice/api/receiving-sip)
* [TwiML Voice: `<Sip>`](/docs/voice/twiml/sip)