After the transaction was suspended, 1st user registered, got INVITE message, there is 2nd user wakes up and send REGISTER.

Kamailio check if transaction suspended (for 2nd user, it is not suspended anymore), and checks if there is stored transaction. So, for 2nd user we have stored transaction, then it should append new branch. ts_append failed.

if ($var(suspended) == 0) { if ($var(stored)) { # no suspended INVITE (i.e. there was at least one # registered contact for target) and 'stored' set # (i.e. ongoing transaction) -> this newly just # registered contact needs alerting. ts_append("location", "sip:$avp(extension)@LOCALVIRTUALIP"); xinfo("appending branches for sip:$avp(extension)@LOCALVIRTUALIP, result $rc"); } else { xinfo("no suspended transactions for $tu"); } return; }

Mar 10 21:07:11 stage-webrtc-kama-01 /usr/sbin/kamailio[4067482]: INFO: [t3jutj5k1na4eir1o8pvk9 REGISTER WAKE_SUSPENDED:1:1339] <script>: -----------122583d4102d400d8565c6f48d217b8d Mar 10 21:07:11 stage-webrtc-kama-01 /usr/sbin/kamailio[4067482]: INFO: [t3jutj5k1na4eir1o8pvk9 REGISTER WAKE_SUSPENDED:1:1348] <script>: var(suspended)=0, tsilo=>suspended::122583d4102d400d8565c6f48d217b8d Mar 10 21:07:11 stage-webrtc-kama-01 /usr/sbin/kamailio[4067482]: INFO: [t3jutj5k1na4eir1o8pvk9 REGISTER WAKE_SUSPENDED:1:1349] <script>: var(stored)=1, tsilo=>stored::122583d4102d400d8565c6f48d217b8d Mar 10 21:07:11 stage-webrtc-kama-01 /usr/sbin/kamailio[4067482]: ERROR: [t3jutj5k1na4eir1o8pvk9 REGISTER WAKE_SUSPENDED:1:1357] tsilo [ts_append.c:152]: ts_append_to(): transaction 11743:1310842517: error updating dset (-1) Mar 10 21:07:11 stage-webrtc-kama-01 /usr/sbin/kamailio[4067482]: INFO: [t3jutj5k1na4eir1o8pvk9 REGISTER WAKE_SUSPENDED:1:1359] <script>: appending branches for sip:1000@10.160.201.190, result 1

At this moment we have active transaction `{ cell: 0x7f313d43cda8 tindex: 11743 tlabel: 1310842517 method: INVITE from: From: "9988" sip:9988@10.156.0.6;tag=as081c0936

to: To: sip:1000@10.160.201.190:5070

callid: Call-ID: 66d9dace125df36915783fb379f4e3dd@10.156.0.6:5060

cseq: CSeq: 102 uas_request: yes tflags: 69 outgoings: 3 ref_count: 1 lifetime: 5402832 } `