SIP/2.0 476 Unresolvable destination

Looks like this:

SEND >> 192.168.0.128:5060
REGISTER sip:opensips SIP/2.0
Via: SIP/2.0/UDP 192.168.0.188:5060;rport;branch=z9hG4bKA99DE09AD2724DD899C20EF23F4DAC70
From: 101 <sip:101@opensips>
To: 101 <sip:101@opensips>
Contact: "101" <sip:101@192.168.0.188:5060>
Call-ID: F0108D09AD144BDE97F352E41C51731B@opensips
CSeq: 48596 REGISTER
Expires: 1800
Max-Forwards: 70
User-Agent: X-PRO build 1082
Content-Length: 0

RECEIVE << 192.168.0.128:5060
SIP/2.0 476 Unresolvable destination (476/TM)
Via: SIP/2.0/UDP 192.168.0.188:5060;rport=5060;branch=z9hG4bKA99DE09AD2724DD899C20EF23F4DAC70
From: 101 <sip:101@opensips>
To: 101 <sip:101@opensips>;tag=6e21fd8f402e36528137555ae7603e02-0879
Call-ID: F0108D09AD144BDE97F352E41C51731B@opensips
CSeq: 48596 REGISTER
Server: OpenSIPS (1.4.2-notls (i386/linux))
Content-Length: 0

---

Check also:

• SIP Error Codes