Thank you Chris and iisnet for suggestion.

Ngnix Error log :
2017/09/09 01:24:17 [emerg] 17449#0: invalid port in “|IP|:|PORT_80|” of the “listen” directive in /etc/nginx/nginx-vhosts.conf:2
2017/09/09 01:41:37 [notice] 27734#0: signal process started
2017/09/09 01:53:43 [emerg] 31974#0: “http2_recv_buffer_size” directive is not allowed here in /usr/local/directadmin/data/users/iphoneap/nginx.conf:158
2017/09/09 02:00:00 [emerg] 33430#0: “ssl_prefer_server_ciphers” directive is duplicate in /etc/nginx/nginx-defaults.conf:29
2017/09/09 02:02:25 [emerg] 34094#0: “http2_recv_buffer_size” directive is not allowed here in /etc/nginx/nginx-events.conf:3
2017/09/09 02:07:27 [emerg] 36405#0: “http2_recv_buffer_size” directive is not allowed here in /usr/local/directadmin/data/users/iphoneap/nginx.conf:165
2017/09/09 02:10:12 [notice] 37055#0: signal process started
2017/09/09 02:10:33 [emerg] 37086#0: “ssl_session_cache” directive is not allowed here in /etc/nginx/nginx.conf:32
2017/09/09 02:10:48 [emerg] 37102#0: “ssl_session_cache” directive is not allowed here in /etc/nginx/nginx.conf:33
2017/09/09 02:12:17 [emerg] 37739#0: “ssl_ciphers” directive is duplicate in /usr/local/directadmin/data/users/iphoneap/nginx.conf:165
2017/09/09 02:13:25 [emerg] 37758#0: “ssl_ciphers” directive is duplicate in /usr/local/directadmin/data/users/iphoneap/nginx.conf:165
2017/09/09 02:14:10 [notice] 37780#0: signal process started

Apache error log :
[Sat Sep 09 01:23:42.120248 2017] [lbmethod_heartbeat:notice] [pid 11995:tid 139905954351040] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 01:23:42.125643 2017] [mpm_event:notice] [pid 11995:tid 139905954351040] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 01:23:42.125796 2017] [core:notice] [pid 11995:tid 139905954351040] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 01:24:02.112928 2017] [mpm_event:notice] [pid 11995:tid 139905954351040] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 01:24:03.016122 2017] [ssl:warn] [pid 15545:tid 140326462146496] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 01:24:03.016363 2017] [suexec:notice] [pid 15545:tid 140326462146496] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 01:24:04.018052 2017] [ssl:warn] [pid 15778:tid 140326462146496] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 01:24:04.018415 2017] [lbmethod_heartbeat:notice] [pid 15778:tid 140326462146496] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 01:24:04.023933 2017] [mpm_event:notice] [pid 15778:tid 140326462146496] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 01:24:04.023993 2017] [core:notice] [pid 15778:tid 140326462146496] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 01:25:05.290881 2017] [core:warn] [pid 15778:tid 140326462146496] AH00045: child process 15878 still did not exit, sending a SIGTERM
[Sat Sep 09 01:25:07.293462 2017] [core:warn] [pid 15778:tid 140326462146496] AH00045: child process 15878 still did not exit, sending a SIGTERM
[Sat Sep 09 01:25:09.296005 2017] [core:warn] [pid 15778:tid 140326462146496] AH00045: child process 15878 still did not exit, sending a SIGTERM
[Sat Sep 09 01:25:11.298634 2017] [core:error] [pid 15778:tid 140326462146496] AH00046: child process 15878 still did not exit, sending a SIGKILL
[Sat Sep 09 01:25:13.029095 2017] [ssl:warn] [pid 18343:tid 139953176242112] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 01:25:13.029744 2017] [suexec:notice] [pid 18343:tid 139953176242112] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 01:25:14.030280 2017] [ssl:warn] [pid 18344:tid 139953176242112] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 01:25:14.031241 2017] [lbmethod_heartbeat:notice] [pid 18344:tid 139953176242112] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 01:25:14.036995 2017] [mpm_event:notice] [pid 18344:tid 139953176242112] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 01:25:14.037132 2017] [core:notice] [pid 18344:tid 139953176242112] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 01:41:34.756846 2017] [mpm_event:notice] [pid 18344:tid 139953176242112] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 01:41:35.024534 2017] [ssl:warn] [pid 26515:tid 140620780279744] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 01:41:35.024966 2017] [suexec:notice] [pid 26515:tid 140620780279744] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 01:41:36.023928 2017] [ssl:warn] [pid 26516:tid 140620780279744] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 01:41:36.024558 2017] [lbmethod_heartbeat:notice] [pid 26516:tid 140620780279744] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 01:41:36.028734 2017] [mpm_event:notice] [pid 26516:tid 140620780279744] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 01:41:36.028832 2017] [core:notice] [pid 26516:tid 140620780279744] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 01:42:01.932602 2017] [mpm_event:notice] [pid 26516:tid 140620780279744] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 01:42:03.034675 2017] [ssl:warn] [pid 28477:tid 140484163475392] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 01:42:03.035083 2017] [suexec:notice] [pid 28477:tid 140484163475392] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 01:42:04.024878 2017] [ssl:warn] [pid 28633:tid 140484163475392] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 01:42:04.025532 2017] [lbmethod_heartbeat:notice] [pid 28633:tid 140484163475392] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 01:42:04.029876 2017] [mpm_event:notice] [pid 28633:tid 140484163475392] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 01:42:04.029980 2017] [core:notice] [pid 28633:tid 140484163475392] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 02:07:21.651181 2017] [mpm_event:notice] [pid 28633:tid 140484163475392] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 02:07:23.034233 2017] [ssl:warn] [pid 35388:tid 139899561912256] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:07:23.034799 2017] [suexec:notice] [pid 35388:tid 139899561912256] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 02:07:24.027120 2017] [ssl:warn] [pid 35389:tid 139899561912256] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:07:24.027755 2017] [lbmethod_heartbeat:notice] [pid 35389:tid 139899561912256] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 02:07:24.031754 2017] [mpm_event:notice] [pid 35389:tid 139899561912256] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 02:07:24.031878 2017] [core:notice] [pid 35389:tid 139899561912256] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 02:28:35.783040 2017] [mpm_event:notice] [pid 35389:tid 139899561912256] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 02:28:36.031744 2017] [ssl:warn] [pid 42717:tid 140341112342464] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:28:36.032293 2017] [suexec:notice] [pid 42717:tid 140341112342464] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 02:28:37.032200 2017] [ssl:warn] [pid 42718:tid 140341112342464] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:28:37.068635 2017] [lbmethod_heartbeat:notice] [pid 42718:tid 140341112342464] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 02:28:37.074005 2017] [mpm_event:notice] [pid 42718:tid 140341112342464] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 02:28:37.074120 2017] [core:notice] [pid 42718:tid 140341112342464] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 02:29:01.528582 2017] [mpm_event:notice] [pid 42718:tid 140341112342464] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 02:29:02.029127 2017] [ssl:warn] [pid 44571:tid 140116376684480] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:29:02.029517 2017] [suexec:notice] [pid 44571:tid 140116376684480] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 02:29:03.024589 2017] [ssl:warn] [pid 44572:tid 140116376684480] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:29:03.025264 2017] [lbmethod_heartbeat:notice] [pid 44572:tid 140116376684480] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 02:29:03.029263 2017] [mpm_event:notice] [pid 44572:tid 140116376684480] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 02:29:03.029368 2017] [core:notice] [pid 44572:tid 140116376684480] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 02:37:01.302801 2017] [mpm_event:notice] [pid 44572:tid 140116376684480] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 02:37:02.038732 2017] [ssl:warn] [pid 48959:tid 140679153174464] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:37:02.039366 2017] [suexec:notice] [pid 48959:tid 140679153174464] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 02:37:03.208799 2017] [ssl:warn] [pid 49033:tid 140679153174464] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:37:03.215742 2017] [lbmethod_heartbeat:notice] [pid 49033:tid 140679153174464] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 02:37:03.224586 2017] [mpm_event:notice] [pid 49033:tid 140679153174464] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 02:37:03.224711 2017] [core:notice] [pid 49033:tid 140679153174464] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 02:37:04.079119 2017] [mpm_event:notice] [pid 49033:tid 140679153174464] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 02:37:05.024942 2017] [ssl:warn] [pid 50236:tid 140183365179328] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:37:05.025329 2017] [suexec:notice] [pid 50236:tid 140183365179328] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 02:37:06.024682 2017] [ssl:warn] [pid 50237:tid 140183365179328] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:37:06.025350 2017] [lbmethod_heartbeat:notice] [pid 50237:tid 140183365179328] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 02:37:06.029407 2017] [mpm_event:notice] [pid 50237:tid 140183365179328] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 02:37:06.029516 2017] [core:notice] [pid 50237:tid 140183365179328] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 02:38:01.674441 2017] [mpm_event:notice] [pid 50237:tid 140183365179328] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 02:38:02.031666 2017] [ssl:warn] [pid 52084:tid 139651287865280] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:38:02.032251 2017] [suexec:notice] [pid 52084:tid 139651287865280] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 02:38:03.028882 2017] [ssl:warn] [pid 52085:tid 139651287865280] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:38:03.029525 2017] [lbmethod_heartbeat:notice] [pid 52085:tid 139651287865280] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 02:38:03.033530 2017] [mpm_event:notice] [pid 52085:tid 139651287865280] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 02:38:03.033676 2017] [core:notice] [pid 52085:tid 139651287865280] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 02:53:18.402870 2017] [mpm_event:notice] [pid 52085:tid 139651287865280] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 02:53:19.024614 2017] [ssl:warn] [pid 57937:tid 140257448908736] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:53:19.025001 2017] [suexec:notice] [pid 57937:tid 140257448908736] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 02:53:20.024446 2017] [ssl:warn] [pid 57938:tid 140257448908736] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:53:20.025144 2017] [lbmethod_heartbeat:notice] [pid 57938:tid 140257448908736] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 02:53:20.029182 2017] [mpm_event:notice] [pid 57938:tid 140257448908736] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 02:53:20.029274 2017] [core:notice] [pid 57938:tid 140257448908736] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 02:54:02.940309 2017] [mpm_event:notice] [pid 57938:tid 140257448908736] AH00491: caught SIGTERM, shutting down
[Sat Sep 09 02:54:04.027340 2017] [ssl:warn] [pid 60097:tid 139656345204672] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:54:04.027742 2017] [suexec:notice] [pid 60097:tid 139656345204672] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Sat Sep 09 02:54:05.029765 2017] [ssl:warn] [pid 60098:tid 139656345204672] AH01909: http://www.example.com:8081:0 server certificate does NOT include an ID which matches the server name
[Sat Sep 09 02:54:05.030538 2017] [lbmethod_heartbeat:notice] [pid 60098:tid 139656345204672] AH02282: No slotmem from mod_heartmonitor
[Sat Sep 09 02:54:05.035379 2017] [mpm_event:notice] [pid 60098:tid 139656345204672] AH00489: Apache/2.4.27 (Unix) OpenSSL/1.0.1e-fips configured — resuming normal operations
[Sat Sep 09 02:54:05.035488 2017] [core:notice] [pid 60098:tid 139656345204672] AH00094: Command line: ‘/usr/sbin/httpd’
[Sat Sep 09 10:09:57.219760 2017] [proxy_fcgi:error] [pid 60164:tid 139655249704704] [client 127.0.0.1:25420] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 10:09:57.224718 2017] [proxy_fcgi:error] [pid 60164:tid 139655041206016] [client 127.0.0.1:25424] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 11:01:34.982918 2017] [proxy_fcgi:error] [pid 60164:tid 139654831408896] [client 127.0.0.1:34114] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 11:01:34.996518 2017] [proxy_fcgi:error] [pid 60164:tid 139654537692928] [client 127.0.0.1:34118] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 11:50:19.836039 2017] [proxy_fcgi:error] [pid 60179:tid 139655114635008] [client 127.0.0.1:42496] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 11:50:19.877037 2017] [proxy_fcgi:error] [pid 60179:tid 139654894348032] [client 127.0.0.1:42500] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 13:01:58.035685 2017] [proxy_fcgi:error] [pid 46079:tid 139654835709696] [client 127.0.0.1:53248] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 13:01:58.041250 2017] [proxy_fcgi:error] [pid 46079:tid 139654846199552] [client 127.0.0.1:53252] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 13:18:11.781190 2017] [proxy_fcgi:error] [pid 46079:tid 139654269257472] [client 127.0.0.1:55580] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php
[Sat Sep 09 13:18:11.785528 2017] [proxy_fcgi:error] [pid 46079:tid 139654825219840] [client 127.0.0.1:55584] AH01071: Got error ‘Primary script unknown\n’, referer: http://ping.rootblog.com/rpc.php

One thing to notice is when I enable HTTP/2 website using NewsMag will return to 502 Bad gateway but other website using other theme it works fine.

yes, my site use HTTPS (SSL) along with PHP 7.1. Thank you for your advice . I will check server error log.

In Visual Composer, it has WP Search box and Tabbed content box but none in TagDiv Composer