Any idea why this INVITE is rejected with 400 Invalid Phone Number by Twilio? The first INVITE asks for Proxy Authentication, that seems to pass and this is rejected. Thank you! INVITE sip:5101112222@mycompany.pstn.twilio.com SIP/2.0 Via: SIP/2.0/UDP 10.50.1.116:5080;rport;branch=z9hG4bKa8QvU1B6QmeKc Max-Forwards: 69 From: "unknown" <sip:4152221111@mycompany.pstn.twilio.com>;tag=6UetZr6rDZgHF To: <sip:5101112222@mycompany.pstn.twilio.com> Call-ID: 1ffda8b7-faaf-1232-8380-a9a65d1e96b1 CSeq: 68751485 INVITE Contact: <sip:gw+twiliotrunk@10.50.1.116:5080;transport=udp;gw=twiliotrunk> Expires: 3600 User-Agent: FreeSWITCH-mod_sofia/1.5.12b~64bit Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY Supported: timer, path, replaces Allow-Events: talk, hold, conference, refer Proxy-Authorization: Digest username="4152221111", realm="sip.twilio.com", nonce="f722ae99d0a818bc422baa5d8", cnonce="IA1gJvqvEg6mmXR6WsQ", opaque="e89d2328e07da020d75a", algorithm=MD5, uri="sip:5101112222@mycompany.pstn.twilio.com", response="e65d3dea5b1e3b35306cfa121ec2ae4d", qop=auth, nc=00000001 Content-Type: application/sdp Content-Disposition: session Content-Length: 268 X-FS-Support: update_display,send_info Remote-Party-ID: "unknown" <sip:1000@mycompany.pstn.twilio.com>;party=calling;screen=yes;privacy=off v=0 o=FreeSWITCH 1418153731 1418153732 IN IP4 10.50.1.116 s=FreeSWITCH c=IN IP4 10.50.1.116 t=0 0 m=audio 21366 RTP/AVP 0 8 3 101 13 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:3 GSM/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ptime:20 -- SIP/2.0 400 Invalid phone number To: <sip:5101112222@ingenio.pstn.twilio.com>;tag=08602519_6772d868_5eef74bb-957c-486e-b261-2a2e63704d73 Via: SIP/2.0/UDP 10.50.1.116:5080;received=10.50.1.116;rport=5080;branch=z9hG4bKa8QvU1B6QmeKc CSeq: 68751485 INVITE Call-ID: 1ffda8b7-faaf-1232-8380-a9a65d1e96b1 From: "unknown" <sip:4152221111@ingenio.pstn.twilio.com>;tag=6UetZr6rDZgHF Contact: <sip:171.118.14.130:5060> Content-Length: 0 --