SIP Register with authentication required (using eXosip2)

->Send Register

->Receive SIP/2.0 407 Proxy Authentication Required with header
Proxy-Authenticate: Digest realm="W.X.Y.Z", nonce="YYYY0992000000046dd64e657218e5a77472ae059c69XXXX"

->Send Register with header
Proxy-Authorization: Digest username="XXXXX", realm="W.X.Y.Z", nonce="YYYY0992000000046dd64e657218e5a77472ae059c69XXXX", uri="sip:W.X.Y.Z", response="ZZZZe5d430141e984ff50fa560bWWWW", algorithm=MD5 ==>1st try

->Receive SIP/2.0 407 Proxy Authentication Required with header
Proxy-Authenticate: Digest realm="W.X.Y.Z", nonce="YYYY0992000000046dd64e657218e5a77472ae059c69XXXX"

->Send Register with header
Proxy-Authorization: Digest username="XXXXX", realm="W.X.Y.Z", nonce="YYYY0992000000046dd64e657218e5a77472ae059c69XXXX", uri="sip:W.X.Y.Z", response="ZZZZe5d430141e984ff50fa560bWWWW", algorithm=MD5 ==>2nd try

->Receive SIP/2.0 407 Proxy Authentication Required with header
Proxy-Authenticate: Digest realm="W.X.Y.Z", nonce="YYYY0992000000046dd64e657218e5a77472ae059c69XXXX"

->Send Register with header
Proxy-Authorization: Digest username="XXXXX", realm="W.X.Y.Z", nonce="YYYY0992000000046dd64e657218e5a77472ae059c69XXXX", uri="sip:W.X.Y.Z", response="ZZZZe5d430141e984ff50fa560bWWWW", algorithm=MD5 ==>3rd try

->Receive SIP/2.0 407 Proxy Authentication Required with header
Proxy-Authenticate: Digest realm="W.X.Y.Z", nonce="YYYY0992000000046dd64e657218e5a77472ae059c69XXXX"