Hi there is an issue with the SIP parser for the t_uac_send function https://www.kamailio.org/docs/modules/devel/modules/tm.html#tm.f.t_uac_send If I call this function for example: t_uac_send("INVITE", "sip:test@123.123.123.123:5060", "", "" ,"Content-Type: text/plain\r\nContact: <sip:85951b3d-096c-95d6-5f05-4f38095aca9f@172.17.64.120:5060;transport=tcp>;+u.sip!devicename.ccm.cisco.com=\"SEP5486BC7F2BBC\"", "Testbody") Then the resulting request is broken - it's probably due to a character (exclamation mark?) in the Contact header.... I tested it with a call from kemi, but it probably also occurs when you run it with a normal kamailio -script tests -- Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/3682 You are receiving this because you are subscribed to this thread. Message ID: &lt;kamailio/kamailio/issues/3682(a)github.com&gt;