title: Twilio SIP Trunking and Sip Domain
body: <p>I am currently using Twilio for my cloud communication platform. A client of ours wants to SIP over to us, with headers, so we can continue the call on our end using Twiml. </p>
  
  <p>I have tried setting up a SIP Domain and it works if I use a soft phone for an end point, but this isn't what I am trying to accomplish. I have also tried setting up a SIP Elastic Trunk and have that trunk connect to our SIP domain which in return call the Voice URL on the SIP domain.  </p>
  
  <p>I currently have setup a simple application to test this process. I have a Twilio number that calls a webhook, in the webhook (my app) I call the sip to the Twilio SIP trunk, but it fails. I am expecting to call the SIP domain and the Voice URL. I keep getting the error that the <strong>You tried to Dial a SIP Endpoint that is not currently registered with the corresponding SIP Domain. Please check your TwiML or REST API.</strong> (reference: <a href="https://www.twilio.com/docs/api/errors/32009" rel="nofollow noreferrer">TWilio Error Documentation</a>.</p>
  
  <p>Can anyone help me with this, please? I am currently using Twiml with PHP.</p>
  
  <p><strong>-- Update --</strong></p>
  
  <p>I am also following this documentation to a tee. I have a SIP Domain setup in my Twilio account, but it is requiring a registered user at an endpoint. In this documentation, it says when a sip call comes into the sip domain it will call the webhook, which it is not doing. <a href="https://www.twilio.com/docs/voice/sip/api/domain" rel="nofollow noreferrer">Twilio SIP Domains</a></p>