Artyom. This could be also related to the speed (Call Attempts Per Second - CAPS) that you are making the outbound calls. If you slow down the outbound calls being made and increase their duration does this increase your simultaneous calls? My guess is similar to your one that this is a provider issue. I know BT in the UK restrict the CAPS on their SIP Trunks to avoid network errors (or basically their SBCs cannot handle more CAPS). Obviously if the provider is generating the NORMAL_CIRCUIT_CONGESTION error (check the SIP Trace) then it is a provider issue and they should be involved. Andrew From: FreeSWITCH-users <freeswitch-users-bounces@lists.freeswitch.org> On Behalf Of Artyom Chernetzov Sent: Wednesday, 20 June 2018 5:22 PM To: freeswitch-users@lists.freeswitch.org Subject: [Freeswitch-users] NORMAL_CIRCUIT_CONGESTION error limiting simultaneous calls We got NORMAL_CIRCUIT_CONGESTION error trying to perform 100 simultaneous calls, and only 40 simultaneous calls actually happen (all other fail with NORMAL_CIRCUIT_CONGESTION). We have 1gbit/s network, all default rtp ports are open, and switch.conf<http://switch.conf>.xml sessions-per-second=1000 (most freeswitch and gateway configs are default). We run dedicated server. Provider tell that 500 lines are available. Is it possible that I missed some config that could limit gateway channels, or this is definitely provider issue?