Can you also paste the "503 service unavailable" packet here? >>>> It does not include any Reason phrase. Is "503" sent from the SIP Server or the caller-A? >>>> Yes Also check the [Result phrase] at [Logs]->[Session Logs]. >>>> web page shows "HTTP Status 500 - Exception caught.".

INVITE sent from A, 200-OK for invite and BYE sent from B are attached: 1.>>>>>> Invite sent from A: INVITE sip:1003@192.168.29.2:5010 SIP/2.0 Via: SIP/2.0/UDP 192.168.29.33:5060;branch=z9hG4bK53a7b4f67d4d-30-18e315 Via: SIP/2.0/TCP 192.168.29.33:62370;rport=62370;branch ...

1. Brekeke Product Name and Version: Brekeke SIP Server, Version 3.6.3.0 2. Java version: no 3. OS type and the version: win10 4. UA (phone), gateway or other hardware/software involved: 5. Your problem: 1). A call B, B answer it; 2). B disconnect the call; from network packets, I can see that B can ...

Thanks.
When second INVITE sent to UA3 has different Call-ID from the original INVITE, the Brekeke server can relay the second INVITE to UA3 sucessfully.

1. Brekeke Product Name and Version: Brekeke SIP Server server-ver 3.6.3.0/454 2. Java version: no 3. OS type and the version: win 10 4. UA (phone), gateway or other hardware/software involved: SIP phone 5. Your problem: UA1 and UA2 register OK in SIP server, UA2 wants to forward all the call to UA3 ...