502 Bad Gateway, PHP FPM Stop Working

I have no idea my server twice a day get 502 bad gateway. I have made lots of tweaks but none of them are working. Here is my dedicated specification

2x E5-2670 0 @ 2.60GHz [32 cores] 32 GB RAM

Here is sample error log

[07-Oct-2022 08:26:19] WARNING: [pool dsimlife-user] child 113207, script '/home/dsimlife/public_html/id1/api-bot.php' (request: "GET /api-bot.php?f=runWork") executing too slow (5.020967 sec), logging
[07-Oct-2022 08:26:19] NOTICE: child 113207 stopped for tracing
[07-Oct-2022 08:26:19] NOTICE: about to trace 113207
[07-Oct-2022 08:26:19] NOTICE: finished trace of 113207
[07-Oct-2022 08:26:24] WARNING: [pool dsimlife-user] child 113218, script '/home/dsimlife/public_html/id1/api-bot.php' (request: "GET /api-bot.php?f=runTask") executing too slow (5.167098 sec), logging
[07-Oct-2022 08:26:24] NOTICE: child 113218 stopped for tracing
[07-Oct-2022 08:26:24] NOTICE: about to trace 113218
[07-Oct-2022 08:26:24] NOTICE: finished trace of 113218

Here is my nginx configuration

user  nobody;
worker_processes 1;
worker_rlimit_nofile 2500;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

pid     /var/run/nginx.pid;
include /usr/local/apps/nginx/etc/modsecurity*.conf;

events {
    worker_connections  1024;
}

error_log /usr/local/apps/nginx/var/log/error_log debug;


http {
    include    mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log /usr/local/apps/nginx/var/log/web.access.log  main;

    sendfile        on;
    #tcp_nopush  on;

    #keepalive_timeout  0;
    keepalive_requests 200;
    keepalive_timeout  130;

    #gzip  on;
    
    client_max_body_size 200M;
    
    # If your domain names are long, increase this parameter.
    server_names_hash_bucket_size 64;
    
    # To hide the version number in headers
    server_tokens off;
    
    include /usr/local/apps/nginx/etc/conf.d/*.conf;
}

Here is my PHP-FPM conf

pm.max_children = 5
pm.start_servers = 0
pm.min_spare_servers = 1
pm.max_spare_servers = 5
pm.max_requests = 20
pm.process_idle_timeout = 10
request_terminate_timeout = 120s

Can anyone tell me what should configuration would be. The main problem is, the server sometime lead to 502 bad gateway where the resource is still fine.