### Description Upon interfacing with a specific carrier’s cloud relay service, upon the termination of the call by the called party after the phone rings, the tag value within the To header of the 408 response from the cloud relay side is altered. When Kamailio relays this 408 response to FreeSwitch, the sofia-sip protocol stack employed by FreeSwitch perceives it as a distinct dialog and does not promptly conclude the call. Given that the carrier’s personnel may lack the capability or the inclination to effect changes, we are looking to accommodate this scenario on the Kamailio side. Upon receipt of the 408 response from the carrier, we will determine if there has been a modification to the tag value in the To header. If such a change is detected, prior to forwarding the 408 response to FreeSwitch, we will rectify the tag value in the To header of the 408 response to correspond with the tag value from the 18x signaling messages. Our system : OS: Rocky Linux release 9.3 (Blue Onyx) Kamailo vesion 5.7.3 ### Troubleshooting #### Reproduction In the kamailio.cfg, invoke a Python script within the onreply_route[MANAGE_REPLY] block The following two scenarios both result in content-related errors: 1. First, the ‘To’ header field is removed using msg.call_function(‘remove_hf’, ‘To’), and then the modified ‘To’ header field is added using msg.call_function(‘append_hf’, sip_to). 2. The tag value in the ‘To’ header field is changed back to the original value using msg.call_function(‘replace_hdrs’, toTag, originalToTag). #### Log Messages Dec 4 13:45:00 sipp102 ./kamailio[391888]: INFO: {2 92091734 INVITE a18e6868-2ca5-123e-a394-00163e347028} app_python3 [mod_Logger.c:172]: logger_LM_INFO(): recv 408, sip_to_field_val = <sip:130679333xx@39.106.31.1xx:5060>;tag=3b47-eb967d112cba8f7d5eb856259e056294 toUri = <sip:130679333xx@39.106.31.1xx:5060> toTag = tag=3b47-eb967d112cba8f7d5eb856259e056294 originalToTag = tag=as73409c31 Dec 4 13:45:00 sipp102 ./kamailio[391888]: CRITICAL: {2 92091734 INVITE a18e6868-2ca5-123e-a394-00163e347028} <core> [core/mem/q_malloc.c:515]: qm_free(): BUG: bad pointer 0x7f60c10a88a0 (out of memory block!) called from app_python3: python_msgobj.c: msg_call_function(258) - ignoring #### SIP Traffic Received 408： Forwarded 408:  -- Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/4050 You are receiving this because you are subscribed to this thread. Message ID: &lt;kamailio/kamailio/issues/4050(a)github.com&gt;