Hi Benny, I've got a problem with stateful_proxy: A Cancel request sometimes causes a software abortion because assertion failed: ../src/pjsip/sip_util.c:556: pjsip_endpt_create_cancel: Assertion `req_tdata->msg->type == PJSIP_REQUEST_MSG && req_tdata->msg->line.req.method.id == PJSIP_INVITE_METHOD' failed. The call flow for this example was: UA pjsip stateful_proxy SIP Server -- -------------------- ---------- Invite -> Invite -> <- trying <- trying <- 407 ACK -> <- 407 CANCEL -> <- 200 Ok --> Assertion failed The assertion failed because in stateful_proxy.c: proxy_on_rx_request: pjsip_endpt_create_cancel: uas_data->uac_tsx->last_tx the ACK message is saved, not the INVITE message. Thank you for help! Best regards, Helmut