for those who use Let’s Encrypt if you try to start kamailio with "systemctl start kamailio " then you tail statis with "systemctl status kamailio.service -l" in /var/log/messages i have see that he search the tls file so : /etc/kamailio/tls.cfg and
[server:default]
method = TLSv1
verify_certificate = no
require_certificate = no
private_key = /etc/letsencrypt/live/MYDOMAIN/privkey.pem
certificate = /etc/letsencrypt/live/MYDOMAIN/fullchain.pem
and restart kamailio i my case he tired me with read file privkey.pem so i have disable the "define WITH_TLS" in file /etc/kamailio/kamailio.cfg in line 152 "/*#!define WITH_TLS*/" then i have reboot kamailio and it's working. now my problme is when i log as agent exemple : agent001 i can access but if i click in "lOGIN TO DIALER" i see "ERROR Login incorrect, please try again. Please contact your Administrator" what wrong here ? screen i have is :
 screen -ls
There are screens on:
        21433.ASTVDadapt        (Detached)
        1517.ASTfastlog (Detached)
        1511.ASTVDremote        (Detached)
        1508.ASTVDauto  (Detached)
        1505.ASTlisten  (Detached)
        1502.ASTsend    (Detached)
        1499.ASTupdate  (Detached)
        1285.asterisk   (Detached)
8 Sockets in /var/run/screen/S-root.

 systemctl status ngcp-rtpengine -l
● ngcp-rtpengine.service - LSB: NGCP rtpengine
   Loaded: loaded (/etc/rc.d/init.d/ngcp-rtpengine; bad; vendor preset: disabled)
   Active: active (running) since Wed 2018-08-29 23:47:53 EDT; 13min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 14528 ExecStop=/etc/rc.d/init.d/ngcp-rtpengine stop (code=exited, status=0/SUCCESS)
  Process: 14552 ExecStart=/etc/rc.d/init.d/ngcp-rtpengine start (code=exited, status=0/SUCCESS)
 Main PID: 14570 (rtpengine)
   CGroup: /system.slice/ngcp-rtpengine.service
           └─14570 /usr/sbin/rtpengine --table=0 --no-fallback --config-file=/etc/rtpengine/rtpengine.conf --listen-ng=80.211.157.116:5066 --pidfile=/var/run/rtpengine.pid

Aug 29 23:47:53 ivrstats systemd[1]: Starting LSB: NGCP rtpengine...
Aug 29 23:47:53 ivrstats ngcp-rtpengine[14552]: Loading module for in-kernel packet forwarding
Aug 29 23:47:53 ivrstats rtpengine[14569]: INFO: Generating new DTLS certificate
Aug 29 23:47:53 ivrstats ngcp-rtpengine[14552]: Starting rtpengine: [  OK  ]
Aug 29 23:47:53 ivrstats systemd[1]: PID file /var/run/rtpengine.pid not readable (yet?) after start.
Aug 29 23:47:53 ivrstats rtpengine[14570]: INFO: Startup complete, version 6.4.0.0-1.el7
Aug 29 23:47:53 ivrstats systemd[1]: Started LSB: NGCP rtpengine.

systemctl status kamailio.service -l
● kamailio.service - Kamailio (OpenSER) - the Open Source SIP Server
   Loaded: loaded (/usr/lib/systemd/system/kamailio.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2018-08-29 23:46:36 EDT; 15min ago
 Main PID: 14201 (kamailio)
   CGroup: /system.slice/kamailio.service
           ├─14201 /usr/sbin/kamailio -DD -P /var/run/kamailio/kamailio.pid -f /etc/kamailio/kamailio.cfg -m 64 -M 4

Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14214]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14237]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14234]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14236]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14235]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14239]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14232]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14232]: INFO: ctl [io_listener.c:214]: io_listen_loop(): io_listen_loop:  using epoll_lt io watch method (config)
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14238]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled
Aug 29 23:46:36 ivrstats /usr/sbin/kamailio[14233]: INFO: rtpengine [rtpengine.c:2209]: rtpp_test(): rtp proxy  found, support for it enabled

 asterisk -rvvv
Asterisk 13.17.2-vici, Copyright (C) 1999 - 2014, Digium, Inc. and others.
Created by Mark Spencer 
Asterisk comes with ABSOLUTELY NO WARRANTY; type 'core show warranty' for details.
This is free software, with components licensed under the GNU General Public
License version 2 and other licenses; you are welcome to redistribute it under
certain conditions. Type 'core show license' for details.
=========================================================================
Connected to Asterisk 13.17.2-vici currently running on ivrstats (pid = 1290)
ivrstats*CLI> sip show peers
Name/username             Host                                    Dyn Forcerport Comedia    ACL Port     Status      Description
8001/8001                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8002/8002                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8003/8003                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8004/8004                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8005/8005                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8006/8006                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8007/8007                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8008/8008                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8009/8009                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8010/8010                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8011/8011                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8012/8012                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8013/8013                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8014/8014                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8015/8015                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8016/8016                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8017/8017                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8018/8018                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8019/8019                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
8020/8020                 (Unspecified)                            D  Yes        Yes            0        UNKNOWN
kamailio                  80.211.157.116                              Yes        Yes            5060     OK (1 ms)
21 sip peers [Monitored: 1 online, 20 offline Unmonitored: 0 online, 0 offline]

any help please ??