Server really slow on wordpress

Hello, anyone have problem with virtualmin on wordpress site ? i have a Wordpress site and it work fine, very fast in few days ago, but now it really slow. I also have a site on same host. that's a Chevereto source code, it's still fast

so i'm not understand what happen to my wordpress site. This is the error log, mostly connect time out by fcgid Anyone can help me out ?

[Wed Aug 21 12:00:17.135094 2019] [fcgid:warn] [pid 7001] (104)Connection reset by peer: [client 207.46.13.175:9402] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:00:44.035419 2019] [fcgid:warn] [pid 7165] (32)Broken pipe: [client 159.203.108.157:32916] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:01:51.021606 2019] [fcgid:warn] [pid 6446] (104)Connection reset by peer: [client 40.77.167.102:2833] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:03:22.822989 2019] [fcgid:warn] [pid 6163] (32)Broken pipe: [client 171.234.234.64:8835] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:03:38.627255 2019] [fcgid:warn] [pid 6446] (104)Connection reset by peer: [client 1.52.121.16:4817] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function, referer: https://www.facebook.com/ [Wed Aug 21 12:05:03.014376 2019] [fcgid:warn] [pid 6626] (32)Broken pipe: [client 68.183.7.158:49988] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:06:28.037324 2019] [fcgid:warn] [pid 2718] (32)Broken pipe: [client 185.244.25.184:35906] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:08:00.253498 2019] [fcgid:warn] [pid 7165] (104)Connection reset by peer: [client 207.46.13.175:5684] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:15:23.252141 2019] [fcgid:warn] [pid 7167] (104)Connection reset by peer: [client 40.77.167.102:8696] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:23:24.361437 2019] [fcgid:warn] [pid 7616] (104)Connection reset by peer: [client 207.46.13.175:12003] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:24:19.534035 2019] [fcgid:warn] [pid 3934] (32)Broken pipe: [client 185.164.72.235:37598] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:26:14.624995 2019] [fcgid:warn] [pid 7016] (32)Broken pipe: [client 159.203.108.157:40810] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:27:30.711525 2019] [fcgid:warn] [pid 6163] (104)Connection reset by peer: [client 207.46.13.175:15031] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:28:49.900175 2019] [fcgid:warn] [pid 7016] (32)Broken pipe: [client 68.183.7.158:41546] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 12:28:50.186279 2019] [fcgid:warn] [pid 6446] (32)Broken pipe: [client 185.244.25.120:59000] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function

[Wed Aug 21 13:04:02.777669 2019] [fcgid:warn] [pid 10074] (32)Broken pipe: [client 5.188.84.75:60488] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function, referer: mydomain[.]com/

[Wed Aug 21 13:48:01.951495 2019] [fcgid:emerg] [pid 11784] (22)Invalid argument: [client 221.132.29.215:41076] mod_fcgid: can't lock process table in pid 11784

[Wed Aug 21 13:48:02.403082 2019] [fcgid:emerg] [pid 12967] (22)Invalid argument: [client 171.252.168.220:28636] mod_fcgid: can't lock process table in pid 12967, referer: mydomain[.]com/

[Wed Aug 21 13:48:02.409542 2019] [fcgid:emerg] [pid 12112] (22)Invalid argument: [client 185.244.25.120:52216] mod_fcgid: can't lock process table in pid 12112

[Wed Aug 21 13:48:02.639082 2019] [fcgid:emerg] [pid 8792] (22)Invalid argument: [client 221.132.29.215:38142] mod_fcgid: can't lock process table in pid 8792

[Wed Aug 21 13:48:02.700460 2019] [fcgid:emerg] [pid 11710] (22)Invalid argument: [client 171.252.168.220:39001] mod_fcgid: can't lock process table in pid 11710, referer: mydomain[.]com/

[Wed Aug 21 13:48:02.713040 2019] [fcgid:emerg] [pid 11789] (22)Invalid argument: [client 221.132.29.215:39520] mod_fcgid: can't lock process table in pid 11789

[Wed Aug 21 13:48:02.834803 2019] [fcgid:warn] [pid 12962] (32)Broken pipe: [client 171.252.168.220:28725] mod_fcgid: ap_pass_brigade failed in handle_request_ipc function, referer: mydomain[.]com/

[Wed Aug 21 13:48:02.835017 2019] [fcgid:emerg] [pid 12962] (22)Invalid argument: [client 171.252.168.220:28725] mod_fcgid: can't lock process table in pid 12962, referer: mydomain[.]com/

[Wed Aug 21 13:48:03.132862 2019] [fcgid:emerg] [pid 13339] (22)Invalid argument: [client 207.46.13.224:1347] mod_fcgid: can't lock process table in pid 13339

[Wed Aug 21 13:48:03.328225 2019] [fcgid:emerg] [pid 12961] (22)Invalid argument: [client 221.132.29.215:42414] mod_fcgid: can't lock process table in pid 12961

[Wed Aug 21 13:48:09.991763 2019] [fcgid:warn] [pid 12803] (104)Connection reset by peer: [client 171.234.234.64:62140] mod_fcgid: error reading data from FastCGI server

[Wed Aug 21 13:48:09.991923 2019] [core:error] [pid 12803] [client 171.234.234.64:62140] End of script output before headers: index.php

[Wed Aug 21 13:48:09.992002 2019] [fcgid:emerg] [pid 12803] (22)Invalid argument: [client 171.234.234.64:62140] mod_fcgid: can't lock process table in pid 12803

[Wed Aug 21 13:48:10.001352 2019] [fcgid:warn] [pid 13264] (104)Connection reset by peer: [client 14.248.124.241:50924] mod_fcgid: error reading data from FastCGI server

[Wed Aug 21 13:48:10.001604 2019] [core:error] [pid 13264] [client 14.248.124.241:50924] End of script output before headers: index.php [Wed Aug 21 13:48:10.001692 2019] [fcgid:emerg] [pid 13264] (22)Invalid argument: [client 14.248.124.241:50924] mod_fcgid: can't lock process table in pid 13264

[Wed Aug 21 13:48:10.027269 2019] [fcgid:warn] [pid 12740] (104)Connection reset by peer: [client 5.188.84.35:51786] mod_fcgid: error reading data from FastCGI server, referer: mydomain[.]com/sua-chua-phan-mem/fpt-f11-treo-logo-flash-file-rom-goc-ok/#comment-10367/

[Wed Aug 21 13:48:10.027410 2019] [core:error] [pid 12740] [client 5.188.84.35:51786] End of script output before headers: index.php, referer: mydomain[.]com/sua-chua-phan-mem/fpt-f11-treo-logo-flash-file-rom-goc-ok/#comment-10367/

[Wed Aug 21 13:48:10.027500 2019] [fcgid:emerg] [pid 12740] (22)Invalid argument: [client 5.188.84.35:51786] mod_fcgid: can't lock process table in pid 12740, referer: mydomain[.]com/sua-chua-phan-mem/fpt-f11-treo-logo-flash-file-rom-goc-ok/#comment-10367/

and this is TOP command

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

3950 root 20 0 42804 4056 3380 R 0.7 0.2 0:04.14 top

8 root      20   0       0      0      0 I   0.3  0.0   0:03.23 rcu_sched

1055 root 20 0 1033808 14356 2732 S 0.3 0.6 0:10.22 fail2ban-server

1 root      20   0  225260   5904   4252 S   0.0  0.2   0:07.56 systemd

2 root      20   0       0      0      0 S   0.0  0.0   0:00.02 kthreadd

4 root       0 -20       0      0      0 I   0.0  0.0   0:00.00 kworker/0:0H

5 root      20   0       0      0      0 I   0.0  0.0   0:00.82 kworker/u8:0

6 root       0 -20       0      0      0 I   0.0  0.0   0:00.00 mm_percpu_wq

7 root      20   0       0      0      0 S   0.0  0.0   0:00.13 ksoftirqd/0

9 root      20   0       0      0      0 I   0.0  0.0   0:00.00 rcu_bh

10 root rt 0 0 0 0 S 0.0 0.0 0:00.01 migration/0

11 root rt 0 0 0 0 S 0.0 0.0 0:00.01 watchdog/0

12 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/0

13 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/1

14 root rt 0 0 0 0 S 0.0 0.0 0:00.02 watchdog/1

15 root rt 0 0 0 0 S 0.0 0.0 0:00.01 migration/1

16 root 20 0 0 0 0 S 0.0 0.0 0:00.14 ksoftirqd/1

17 root 20 0 0 0 0 I 0.0 0.0 0:01.13 kworker/1:0

18 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/1:0H

19 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/2

20 root rt 0 0 0 0 S 0.0 0.0 0:00.01 watchdog/2

21 root rt 0 0 0 0 S 0.0 0.0 0:00.00 migration/2

22 root 20 0 0 0 0 S 0.0 0.0 0:00.15 ksoftirqd/2

24 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/2:0H

25 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuhp/3

26 root rt 0 0 0 0 S 0.0 0.0 0:00.01 watchdog/3

27 root rt 0 0 0 0 S 0.0 0.0 0:00.00 migration/3

28 root 20 0 0 0 0 S 0.0 0.0 0:00.28 ksoftirqd/3

30 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/3:0H

31 root 20 0 0 0 0 S 0.0 0.0 0:00.01 kdevtmpfs

32 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 netns

33 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_tasks_kthre

34 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kauditd

35 root 20 0 0 0 0 I 0.0 0.0 0:00.43 kworker/0:1

36 root 20 0 0 0 0 S 0.0 0.0 0:00.00 khungtaskd

37 root 20 0 0 0 0 S 0.0 0.0 0:00.00 oom_reaper

38 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 writeback

39 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kcompactd0

40 root 25 5 0 0 0 S 0.0 0.0 0:00.00 ksmd

41 root 39 19 0 0 0 S 0.0 0.0 0:00.00 khugepaged

42 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 crypto

43 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kintegrityd

44 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kblockd

45 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 ata_sff

46 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 md

47 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 edac-poller

root@localhost:~#

i already restart my vps, restart webmin, apache2, but still slow, change fcgid to CGI or mod_php FPM not help me alot.

Mysql database i just drop and restore old db i 've backup on last sunday, but problem still there, very slow.