The error messages says it is a problem with the permissions. Open your PHP-FPM pool and check the value for listen.owner and listen.group. Make sure that the Mautic files are owned by that user. Thanks

Here is the nginx error log:
2018/06/28 18:45:24 [crit] 24073#0: *11 connect() to unix:/var/run/php-fpm/php-fpm.sock failed (13: Permission denied) while connecting to upstream, client: XX.XXX.XX.XXX, server: server.mydomain.com, request: “GET /index.php HTTP/1.1”, upstream: “fastcgi://unix:/var/run/php-fpm/php-fpm.sock:”, host: “server.mydomain.com”

You can check your log files for errors or more information about the problem you are experiencing. Thanks.

can you please guide ? , I am getting “The site is currently offline due to encountering an error”
my default site conf
” server {
listen 80;
server_name domain.com;

access_log /var/log/nginx/domain.com.access_log;
error_log /var/log/nginx/domain.com.error_log;

root /var/www/html;
index index.php index.htm index.html;

include /etc/nginx/global/wordpress.conf;
include /etc/nginx/global/restrictions.conf;
include /etc/nginx/global/mautic.conf;
}
”
and mautic.conf
“server {
server_name domain.com/mautic;
listen 80;
root /var/www/html/mautic/public_html;

access_log /var/www/html/mautic/logs/access.log;
error_log /var/www/html/mautic/logs/error.log;

index index.php;

location / {
try_files $uri $uri/ /index.php?$query_string;
}

sendfile off;

location ~ \.php$ {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_intercept_errors off;
fastcgi_buffer_size 16k;
fastcgi_buffers 4 16k;
}

location ~ /\.ht {
deny all;
}
}
“

Yes, you can install Mautic in a subdirectory. As for creating Nginx virtual config it is totally up to you.

Just find out it was a typo. Sorry to bother :)

Please check the Nginx error log for more info