I receive this following mail. There are a problem in authentication's step. I think the problem becomes : realm="BroadWorks" in SvSIP realm="SIP_DOMAIN" (simplification of config file) Do I have reason ? Samuel -->> Great to see a SIP client for the DS, many thanks! I'm having trouble authenticating, so I thought I'd share the reason (and SvSIP log): Response to initial (no auth) rego from SIP server to SvSIP: SIP/2.0 401 Unauthorized Via: SIP/2.0/UDP 192.168.*.*:5060;received=*.*.*.*;branch=z9hG4bKPjffff00000003ff8a4374;rport=5060 From: <sip:12345678@xxxxxxxxxxxxxxxx>;tag=ffff00000002ff8a4374 To: <sip:87654321 at sip.provider.com> Call-ID: ffff00000001ff8a4374 CSeq: 29728 REGISTER WWW-Authenticate: DIGEST realm="BroadWorks",qop="auth",algorithm=MD5,nonce="BroadWorksXf6ozdtl7T3o7wlmBW" Content-Length: 0 The result on SvSIP's end was: 22:29:53.000 sip_auth_clien Unable to set auth for tdta0x21e899c: can not find credential for BroadWorks/DIGEST 22:29:53.000 pjsua_acc.c SIP registration error: No suitable credential (PJSIP_ENOCREDENTIAL) [status=171101] After which it just tried to call anyhow and went on to send the INVITE. Just for reference, Broadsoft (http://www.broadsoft.com <http://imp.free.fr/horde/util/go.php?url=http%3A%2F%2Fwww.broadsoft.com&Horde=411a113709ef62b10a9ba0f01b0e9fe4>) is the creator of an industrial-strength VoIP platform called BroadWorks, which is sold to a number of commercial providers. I think 'DIGEST' refers to bog standard digest authentication (that we all know and love), but I'm not sure. Is it possible to get a greater range of authentication protocols defined in SvSIP at some point in the future? :) Best of luck!