I'm using FreePBX/Trixbox with Asterisk 1.4.17-1 trying to register against a Sylantro server in front of a Metaswitch. I'm able to register and receive inbound calls but outbound calls are rejected by the far end. The username and password have been checked repeatedly. Putting the same authentication and server IP into a softphone or polycom phone work fine for inbound and outbound calls. Has anyone made this work in the past? This is the rejection sent by the switch at the other end: SIP/2.0 403 Forbidden Via: SIP/2.0/UDP 10.1.4.110:5060;received=67.55.x.x;branch=z9hG4bK71d476d2;rport=5060 From: "515XXXXXXX" <sip:515XXXXXXX at 10.1.4.110>;tag=as6a5cd6c8 To: <sip:YYYYYYY at Z.Z.Z.Z>;tag=aprqngfrt-n2bk9j10000c6 Call-ID: 116d504b7b5fc29b6321786f5325cbc2 at 10.1.4.110 CSeq: 102 INVITE dave