Thanks you very much, this seems exactly what I need. Regards, David From: Daniel-Constantin Mierla &lt;miconda(a)gmail.com&gt; Sent: Tuesday, August 24, 2021 4:24 PM To: Kamailio (SER) - Users Mailing List &lt;sr-users(a)lists.kamailio.org&gt;rg>; David VILLAUME &lt;david.villaume(a)sewan.fr&gt; Subject: Re: [SR-Users] Race conditions upon quick reinvite Hello, see if setting this core parameter helps: * https://www.kamailio.org/wiki/cookbooks/5.5.x/core#route_locks_size An alternative would be to use htable to store the time when the 200ok (or ACK) is processed and if the re-INVITE comes very fast, do a sleep()/usleep(). Cheers, Daniel On 24.08.21 15:12, David VILLAUME wrote: Hello, We encounter sometimes reinvite from some provider really quickly after 200 OK ACK so sometime there a race conditions where the re-invite exits Kamailio before the ACK leading to some Freeswitch “500 Overlapping Requests”. [cid:image001.png@01D79906.F7DC6A70] I tried to catch the 500 on failure-route unsuccessfully as transaction is already established. Do you have any idea on how I could deal with this behavour ? Running 5.3.6 with 8 childs modules used :(tm + dialog) No costly action performed on ack that can explain slowliness. Regards, David __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions * sr-users@lists.kamailio.org<mailto:sr-users@lists.kamailio.org> Important: keep the mailing list in the recipients, do not reply only to the sender! Edit mailing list options or unsubscribe: * https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users -- Daniel-Constantin Mierla -- www.asipto.com<http://www.asipto.com> www.twitter.com/miconda<http://www.twitter.com/miconda> -- www.linkedin.com/in/miconda<http://www.linkedin.com/in/miconda>