--- "@context": https://schema.org "@type": TechArticle "@id": https://www.twilio.com/docs/api/errors/13255#article headline: "13255: Dialing .sip.twilio.com addresses is not currently allowed" url: https://www.twilio.com/docs/api/errors/13255 inLanguage: en dateModified: 2026-06-08T11:38:30.000Z author: "@type": Organization name: Twilio Developer Education Team publisher: "@type": Organization name: Twilio --- # 13255: Dialing .sip.twilio.com addresses is not currently allowed Log Level: WARNING ## Description This warning appears when your application tries to dial a `.sip.twilio.com` destination in a call flow that does not support internal SIP routing. Use `` to send a call to your own SIP infrastructure. If you are calling a registered SIP endpoint on a Twilio SIP Domain, dial the endpoint's full Address of Record, such as `username@yourdomain.sip.twilio.com`. ### Possible causes * You attempted to dial a Twilio SIP Domain directly from a Twilio phone number or an active call. * You used a bare SIP Domain such as `yourdomain.sip.twilio.com` instead of a full registered endpoint address such as `username@yourdomain.sip.twilio.com`. * You attempted to route a SIP call between Twilio SIP Domains instead of to an external SIP endpoint or a registered SIP endpoint. ### Possible solutions * If you need to send the call to your SIP infrastructure, update your TwiML or REST API request to dial your own SIP URI with ``. * If you need to reach a registered SIP endpoint on a Twilio SIP Domain, use the full Address of Record in the destination, such as `username@yourdomain.sip.twilio.com`. * Verify that the username in the SIP URI matches a SIP endpoint that is currently registered on your SIP Domain. * Replace unsupported `.sip.twilio.com` destinations that do not identify a registered SIP endpoint. #### Additional resources * [Use SIP with Twilio Voice](/docs/voice/api/sip-interface) * [SIP Registration](/docs/voice/api/sip-registration) * [TwiML Voice: ``](/docs/voice/twiml/sip)