I have an account from CIK (www.CIKTel.com). This account is supposed to be an extension in CIK system, i.e. using SIP phone. I want to config it as a trunk in asterisk. This is my trunk setting canreinvite=no context=from-trunk fromdomain=CMTor1.ciktel.com fromuser=xxxxxxx host=CMTor1.ciktel.com insecure=very nat=yes qualify=yes secret=yyyy type=friend username=zzzzzzzzz Note that CIK has different username and auth id. With the above setting, I can make call from asterisk. But I kept getting SERVICE UNAVAILABE in the log and I could not receive any call. I got the same symptom when using other provider (extension, not real trunk) Anyone has any idea.