Hello, what do you want to do when the 2nd branch does not reply a 487 to the internally generated CANCEL? Send it another four times? This branch has ended already, due to the pickup on the 1st branch. Cheers, Henning From: Richard Chan <shihping.chan(a)gmail.com> Sent: Freitag, 31. März 2023 02:12 To: Kamailio (SER) - Users Mailing List <sr-users(a)lists.kamailio.org> Subject: [SR-Users] CANCEL timeout in branch route does not trigger any failure routes Hi Kamailio users How can I get a failure route to trigger in timeout-to-CANCEL in a parallel forking scenario? Parallel forking test scenario 1. one(the main - 0) branch picks up the call 2. 2nd branch sends CANCEL (expecting 487 etc) - but the callee does not send any replies Result: No failure route handlers are called on timeout of this CANCEL - that is kamailio attempts the CANCEL 4 times but neither tm.t_on_failure_route, tm.t_on_branch_failure handlers are called. Any suggestions on how to resolve this? Regards Shih-Ping