Hello, During some call peaks, FS replies with 503 Maximum Calls and produces the following log: /var/log/freeswitch/freeswitch.log.2016-12-12-10-20-33.1:2016-12-12 10:08:54.964919 [CRIT] switch_core_session.c:2270 Over Session Limit! 973 /var/log/freeswitch/freeswitch.log.2016-12-12-10-20-33.1:2016-12-12 10:08:54.964919 [CRIT] mod_sofia.c:4406 Error Creating Sessi I dig into the configuration to change many settings related to this error. So, our current "status" is: FreeSWITCH (Version 1.6.5 git 70b8c17 2015-11-20 20:57:50Z 64bit) is ready 1207363 session(s) since startup 684 session(s) - peak 983, last 5min 694 0 session(s) per Sec out of max 400, peak 164, last 5min 8 973 session(s) max min idle cpu 0.00/39.77 Current Stack Size/Max 240K/8192K I don't understand how the 973 sessions max is determined? The switch.conf.xml is set as follow: <settings> <param name="colorize-console" value="true"/> <param name="dialplan-timestamps" value="false"/> <param name="max-db-handles" value="50"/> <param name="db-handle-timeout" value="10"/> <param name="max-sessions" value="4000"/> <param name="sessions-per-second" value="400"/> <param name="loglevel" value="debug"/> <param name="mailer-app" value="sendmail"/> <param name="mailer-app-args" value="-t"/> <param name="dump-cores" value="yes"/> <param name="rtp-enable-zrtp" value="false"/> <param name="min-idle-cpu" value="0"/> <param name="enable-clock-nanosleep" value="true"/> </settings> I also made modifications to the OS himself, into limits.conf: freeswitch hard nofile 500000 freeswitch soft nofile 500000 freeswitch hard nproc 62815 freeswitch soft nproc 62815 The setup looks to be active: # cat /proc/25695/limits Limit Soft Limit Hard Limit Units Max cpu time unlimited unlimited seconds Max file size unlimited unlimited bytes Max data size unlimited unlimited bytes Max stack size 245760 8388608 bytes Max core file size unlimited unlimited bytes Max resident set unlimited unlimited bytes Max processes 62815 62815 processes Max open files 500000 500000 files Max locked memory 65536 65536 bytes Max address space unlimited unlimited bytes Max file locks unlimited unlimited locks Max pending signals 62815 62815 signals Max msgqueue size 819200 819200 bytes Max nice priority 0 0 Max realtime priority 0 0 Max realtime timeout unlimited unlimited us Any idea? Thanks. Regards, Igor.