FIX: PHP-FPM Not Working (503 Service Unavailable)

Go to cwp dashboard, then click Webserver Settings->WebServers Conf Editor, Select PHP-FPM menu then click on "/opt/alt/php-fpmxx/usr/etc/php-fpm.d/users/"

Now, click on "Add New Conf File" here you will create filename of your user name: account_username.conf.

Then try using these code into the file:

account_username]
listen = /opt/alt/php-fpm74/usr/var/sockets/account_username.sock
listen.allowed_clients = 127.0.0.1

;listen.owner = "account_username"
listen.group = "nobody"
listen.mode = 0660
user = "account_username"
group = "account_username"

;request_slowlog_timeout = 15s
;slowlog = /opt/alt/php-fpm74/usr/var/log/php-fpm-slowlog-account_username.log

pm = ondemand
pm.max_children = 4
pm.max_requests = 4000
pm.process_idle_timeout = 15s

;listen.backlog = -1
;request_terminate_timeout = 0s
rlimit_files = 131072
rlimit_core = unlimited
catch_workers_output = yes

env[HOSTNAME] = $HOSTNAME
env[TMP] = /home/account_username/tmp
env[TMPDIR] = /home/account_username/tmp
env[TEMP] = /home/account_username/tmp
env[PATH] = /usr/local/bin:/usr/bin:/bin

Change just the "account_username" and php-fpm version with yours, after finish restart phpfpm : service php-fpm74 restart
You can use FTP and do the same navigating to : "/opt/alt/php-fpmxx/usr/etc/php-fpm.d/users/"