A follow up... I have found that all my other phones have codec preferences set to 711u, 711a, 729. The Mitels were configured as 722, 711u, 711a. Could this be a problem with the codec changing when the call connects? Sean From: FreeSWITCH-users <freeswitch-users-bounces@lists.freeswitch.org> On Behalf Of Sean Devoy Sent: Tuesday, April 30, 2019 12:24 PM To: FreeSWITCH Users Help <freeswitch-users@lists.freeswitch.org> Subject: [Freeswitch-users] Call Drop ( we think only when originated by Mitel phone) FreeSWITCH Version 1.8.5-6-31281a0bf1~64bit (-6-31281a0bf1 64bit) The server is offsite and not NATed, the phones are NATed. My customer got some Mitel 6867i phones. They are working fine 95% of the time. We have narrowed it down we think but this may be anecdotal based on limited data. It appears to only happen when a call is originated from these Mitel phones. Cisco phones at the same site are rock solid. The customer reports "dropped calls". I got a Mitel 6867i and tested. After 44 test calls, I got a dropped call within seconds of being answered. Another instance where user actually gave me enough information to track it down showed the exact same thing - hangup after 7 seconds. Here is a log extract at the point where I answer the test call. sofia/external/4104440002 is the Mitel originating phone. 15:52:04.041308 [NOTICE] sofia.c:8429 Channel [sofia/internal/314] has been answered 15:52:04.041308 [DEBUG] switch_channel.c:3781 (sofia/internal/314) Callstate Change EARLY -> ACTIVE 15:52:04.041308 [DEBUG] switch_core_codec.c:248 sofia/external/4104440002@66.241.96.237<mailto:sofia/external/4104440002@66.241.96.237> Restore previous codec PCMU:0. 15:52:04.041308 [DEBUG] switch_ivr_originate.c:3798 Originate Resulted in Success: [sofia/internal/314] 15:52:04.041308 [DEBUG] switch_channel.c:2047 (sofia/external/4104440002@66.241.96.237<mailto:sofia/external/4104440002@66.241.96.237>) Callstate Change RING_WAIT -> ACTIVE 15:52:04.041308 [DEBUG] switch_ivr_bridge.c:1782 (sofia/internal/314) State Change CS_CONSUME_MEDIA -> CS_EXCHANGE_MEDIA 15:52:04.041308 [DEBUG] switch_core_state_machine.c:584 (sofia/internal/314) Running State Change CS_EXCHANGE_MEDIA (Cur 4 Tot 1109) 15:52:04.041308 [DEBUG] switch_core_state_machine.c:653 (sofia/internal/314) State EXCHANGE_MEDIA 15:52:04.041308 [DEBUG] mod_sofia.c:646 SOFIA EXCHANGE_MEDIA 15:52:04.101306 [DEBUG] switch_rtp.c:7550 Correct audio ip/port confirmed. 15:52:07.501320 [NOTICE] sofia.c:1079 Hangup sofia/external/4104440002@66.241.96.237<mailto:sofia/external/4104440002@66.241.96.237> [CS_EXECUTE] [NORMAL_CLEARING] 15:52:07.501320 [DEBUG] switch_ivr_bridge.c:917 BRIDGE THREAD DONE [sofia/external/4104440002@66.241.96.237] 15:52:07.521295 [DEBUG] switch_ivr_bridge.c:825 sofia/external/4104440002@66.241.96.237<mailto:sofia/external/4104440002@66.241.96.237> ending bridge by request from write function 15:52:07.521295 [DEBUG] switch_ivr_bridge.c:917 BRIDGE THREAD DONE [sofia/internal/314] 15:52:07.521295 [NOTICE] switch_ivr_bridge.c:1034 Hangup sofia/internal/314 [CS_EXCHANGE_MEDIA] [NORMAL_CLEARING] 15:52:07.521295 [DEBUG] switch_core_state_machine.c:653 (sofia/internal/314) State EXCHANGE_MEDIA going to sleep 15:52:07.521295 [DEBUG] switch_core_state_machine.c:584 (sofia/internal/314) Running State Change CS_HANGUP (Cur 4 Tot 1109) 15:52:07.521295 [DEBUG] switch_core_state_machine.c:847 (sofia/internal/314) Callstate Change ACTIVE -> HANGUP 15:52:07.521295 [DEBUG] switch_ivr_bridge.c:1881 sofia/internal/314 skip receive message [UNBRIDGE] (channel is hungup already) 15:52:07.521295 [DEBUG] switch_ivr_bridge.c:1884 sofia/external/4104440002@66.241.96.237<mailto:sofia/external/4104440002@66.241.96.237> skip receive message [UNBRIDGE] (channel is hungup already) 15:52:07.521295 [DEBUG] switch_core_state_machine.c:849 (sofia/internal/314) State HANGUP 15:52:07.521295 [DEBUG] mod_sofia.c:443 sofia/internal/314 Overriding SIP cause 480 with 200 from the other leg 15:52:07.521295 [DEBUG] mod_sofia.c:449 Channel sofia/internal/314 hanging up, cause: NORMAL_CLEARING 15:52:07.521295 [DEBUG] switch_core_session.c:2887 sofia/external/4104440002@66.241.96.237<mailto:sofia/external/4104440002@66.241.96.237> skip receive message [APPLICATION_EXEC_COMPLETE] (channel is hungup already) 15:52:07.521295 [DEBUG] switch_core_session.c:2887 sofia/external/4104440002@66.241.96.237<mailto:sofia/external/4104440002@66.241.96.237> skip receive message [APPLICATION_EXEC_COMPLETE] (channel is hungup already) Any ideas why this is happening? Anyone know any secrets about Mitel phones other then use TCP instead of UDP? Any ideas on how to debug this further since it happens so rarely? Thanks, Sean