Update: I have checked error logs in this file:
$ vi /usr/local/cwpsrv/logs/error_log
with some of its content shown below:
2018/07/22 05:57:53 [notice] 13844#0: ModSecurity for nginx (STABLE)/2.9.2 (
http://www.modsecurity.org/) configured.
2018/07/22 05:57:53 [notice] 13844#0: ModSecurity: APR compiled version="1.6.2"; loaded version="1.6.2"
2018/07/22 05:57:53 [notice] 13844#0: ModSecurity: PCRE compiled version="8.32 "; loaded version="8.32 2012-11-30"
2018/07/22 05:57:53 [notice] 13844#0: ModSecurity: LIBXML compiled version="2.9.1"
2018/07/22 05:57:53 [notice] 13844#0: ModSecurity: Original server signature: ModSecurity Standalone
2018/07/22 05:57:53 [notice] 13844#0: ModSecurity: Status engine is currently disabled, enable it by set SecStatusEngine to On.
2018/07/22 05:57:53 [notice] 13845#0: ModSecurity for nginx (STABLE)/2.9.2 (
http://www.modsecurity.org/) configured.
2018/07/22 05:57:53 [notice] 13845#0: ModSecurity: APR compiled version="1.6.2"; loaded version="1.6.2"
2018/07/22 05:57:53 [notice] 13845#0: ModSecurity: PCRE compiled version="8.32 "; loaded version="8.32 2012-11-30"
2018/07/22 05:57:53 [notice] 13845#0: ModSecurity: LIBXML compiled version="2.9.1"
2018/07/22 05:57:53 [notice] 13845#0: ModSecurity: Original server signature: ModSecurity Standalone
2018/07/22 05:57:53 [notice] 13845#0: ModSecurity: Status engine is currently disabled, enable it by set SecStatusEngine to On.
2018/07/22 05:58:10 [notice] 752#0: ModSecurity for nginx (STABLE)/2.9.2 (
http://www.modsecurity.org/) configured.
2018/07/22 05:58:10 [notice] 752#0: ModSecurity: APR compiled version="1.6.2"; loaded version="1.6.2"
2018/07/22 05:58:10 [notice] 752#0: ModSecurity: PCRE compiled version="8.32 "; loaded version="8.32 2012-11-30"
2018/07/22 05:58:10 [notice] 752#0: ModSecurity: LIBXML compiled version="2.9.1"
2018/07/22 05:58:10 [notice] 752#0: ModSecurity: Original server signature: ModSecurity Standalone
2018/07/22 05:58:10 [notice] 752#0: ModSecurity: Status engine is currently disabled, enable it by set SecStatusEngine to On.
2018/07/22 05:58:11 [notice] 789#0: ModSecurity for nginx (STABLE)/2.9.2 (
http://www.modsecurity.org/) configured.
2018/07/22 05:58:11 [notice] 789#0: ModSecurity: APR compiled version="1.6.2"; loaded version="1.6.2"
2018/07/22 05:58:11 [notice] 789#0: ModSecurity: PCRE compiled version="8.32 "; loaded version="8.32 2012-11-30"
2018/07/22 05:58:11 [notice] 789#0: ModSecurity: LIBXML compiled version="2.9.1"
2018/07/22 05:58:11 [notice] 789#0: ModSecurity: Original server signature: ModSecurity Standalone
2018/07/22 05:58:11 [notice] 789#0: ModSecurity: Status engine is currently disabled, enable it by set SecStatusEngine to On.
2018/07/22 05:59:59 [error] 794#0: *2 open() "/usr/local/cwpsrv/htdocs/admin/favicon.ico" failed (2: No such file or directory), client: 82.23.219.148, server: localhost, request: "GET /favicon.ico HTTP/1.1", host: "167.114.98.75:2030", referrer: "
http://167.114.98.75:2030/login/index.php"
2018/07/22 06:07:32 [error] 794#0: *10 FastCGI sent in stderr: "PHP message: PHP Warning: mysqli::__construct(): (HY000/1049): Unknown database 'oauthv2' in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0
PHP message: PHP Notice: Trying to get property of non-object in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0" while reading upstream, client: 82.23.219.148, server: localhost, request: "GET /admin/index.php?module=fast_login HTTP/1.1", upstream: "fastcgi://unix:/usr/local/cwp/php71/var/sockets/cwpsrv.sock:", host: "167.114.98.75:2030", referrer: "
http://167.114.98.75:2030/login/index.php"
2018/07/22 06:07:59 [error] 794#0: *10 FastCGI sent in stderr: "PHP message: PHP Warning: mysqli::__construct(): (HY000/1049): Unknown database 'oauthv2' in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0
PHP message: PHP Notice: Trying to get property of non-object in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0" while reading upstream, client: 82.23.219.148, server: localhost, request: "GET /admin/index.php?module=nameservers HTTP/1.1", upstream: "fastcgi://unix:/usr/local/cwp/php71/var/sockets/cwpsrv.sock:", host: "167.114.98.75:2030", referrer: "
http://167.114.98.75:2030/admin/index.php?module=fast_login"
2018/07/22 06:08:30 [error] 794#0: *10 FastCGI sent in stderr: "PHP message: PHP Warning: mysqli::__construct(): (HY000/1049): Unknown database 'oauthv2' in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0
PHP message: PHP Notice: Trying to get property of non-object in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0" while reading upstream, client: 82.23.219.148, server: localhost, request: "POST /admin/index.php?module=nameservers HTTP/1.1", upstream: "fastcgi://unix:/usr/local/cwp/php71/var/sockets/cwpsrv.sock:", host: "167.114.98.75:2030", referrer: "
http://167.114.98.75:2030/admin/index.php?module=nameservers"
2018/07/22 06:08:42 [error] 795#0: *36 FastCGI sent in stderr: "PHP message: PHP Warning: mysqli::__construct(): (HY000/1049): Unknown database 'oauthv2' in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0
PHP message: PHP Notice: Trying to get property of non-object in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0" while reading upstream, client: 82.23.219.148, server: localhost, request: "GET /admin/index.php?module=settings HTTP/1.1", upstream: "fastcgi://unix:/usr/local/cwp/php71/var/sockets/cwpsrv.sock:", host: "167.114.98.75:2030", referrer: "
http://167.114.98.75:2030/admin/index.php?module=nameservers"
2018/07/22 06:08:52 [error] 794#0: *10 FastCGI sent in stderr: "PHP message: PHP Warning: mysqli::__construct(): (HY000/1049): Unknown database 'oauthv2' in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0
PHP message: PHP Notice: Trying to get property of non-object in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0" while reading upstream, client: 82.23.219.148, server: localhost, request: "POST /admin/index.php?module=settings HTTP/1.1", upstream: "fastcgi://unix:/usr/local/cwp/php71/var/sockets/cwpsrv.sock:", host: "167.114.98.75:2030", referrer: "
http://167.114.98.75:2030/admin/index.php?module=settings"
2018/07/22 06:09:12 [error] 795#0: *36 FastCGI sent in stderr: "PHP message: PHP Warning: mysqli::__construct(): (HY000/1049): Unknown database 'oauthv2' in /usr/local/cwpsrv/htdocs/resources/admin/include/functions.php on line 0
What could cause the slowness of CWP?
Very appreciate your help.