sipp keeps resending message

Question

In a sipp scenario involving a register, I am getting the following error:

Discarding message which can't be mapped to a known SIPp call:

What I am seeing in the message log is a continuous repeat of the first message, a REGISTER message:

                             Messages  Retrans   Timeout   Unexpected-Msg
          [ NOP ]              
REGISTER ---------->         1         9         1                         
          [ NOP ]              
     401 <----------         0         0         0         0               
REGISTER ---------->         0         0         0                         
     200 <----------         0         0         0         0               
  INVITE ---------->         0         0         0                         
     100 <----------         0         0         0         0               
     180 <----------         0         0         0         0               
     183 <----------         0         0         0         0               
     200 <----------  E-RTD1 0         0         0         0               
     ACK ---------->         0         0                                   
   Pause [   5000ms]         0                             0        
     BYE ---------->         0         0         0                         
     200 <----------         0         0         0         0               

What cause cause the Call-ID to mismatch?

I am using SIPp v3.6.0-4-gcc24f9d-TLS-SCTP-PCAP-RTPSTREAM

Answer 1

In the sipp scenario at https://github.com/rkday/sipp-samples/blob/master/uac-auth.xml, the Call-ID: was:

Call-ID: [call_id]///REGISTER

Removing the "///REGISTER" has fixed this, sipp now proceeds with the other messages.