HELP! No app page show/ show with 502 bad Gateway empty blank after configure: Admin account; stored directory and database user

Dear everyone!

I am a newbie for both nginx and nextcloud. After several days reading; installation and wakeup the block server with the following basic specs as:

  • Linux server - Ubuntu 18.04LTS
  • Odoo12 server on Ubuntu
  • Nextcloud server on Ubuntu - the same as Odoo
  • Database - Both use PostgreSQL
  • PHP7.2 with it’s extension
  • domain: 1. mydomain1.com for ODoo12 ; 2. mydomain2.com for Nextcloud both is root seperately root domain using one public IP
  • Webserver: Nginx
  • SSL certificate: Certbot with snippets for renew

the Odoo server is running well. But the Nextcloud server with the bad gateway shown after I configured admin account, stored directory and Database via secure web (successfully with ssl).

NC has installed under root www directory - /var/www/nextcloud

No more I can do, because the Broswer show 502 Bad Gateway when Nextcloud (NC) try to open the apps page.

Here is my nginx conf file (/etc/nginx/sites-available/mydomain2.com (my 2nd domain name):

upstream php-handler {
    server 127.0.0.1:9000;
   #server unix:/var/run/php/php7.0-fpm.sock;
}

server {
   listen 80;
   server_name www.golive.vn golive.vn;

   include snippets/letsencrypt.conf;
   return 301 https://$host$request_uri;
}

server {
    listen 443 ssl http2;
    server_name www.golive.vn;

   ssl_certificate /etc/letsencrypt/live/golive.vn/fullchain.pem;
   ssl_certificate_key /etc/letsencrypt/live/golive.vn/privkey.pem;
   ssl_trusted_certificate /etc/letsencrypt/live/golive.vn/chain.pem;
   include snippets/ssl.conf;
   include snippets/letsencrypt.conf;

  return 301 https://golive.vn$request_uri;
}

server {
  listen 443 ssl http2;
  server_name golive.vn;

  ssl_certificate /etc/letsencrypt/live/golive.vn/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/golive.vn/privkey.pem;
  ssl_trusted_certificate /etc/letsencrypt/live/golive.vn/chain.pem;
  include snippets/ssl.conf;
  include snippets/letsencrypt.conf;

  add_header X-Content-Type-Options nosniff;
  add_header X-XSS-Protection "1; mode=block";
  add_header X-Content-Type-Options nosniff;
  add_header X-XSS-Protection "1; mode=block";
  add_header X-Robots-Tag none;
  add_header X-Download-Options noopen;
  add_header X-Permitted-Cross-Domain-Policies none;

  root /var/www/nextcloud/;

  location = /robots.txt {
      allow all;
      log_not_found off;
      access_log off;
  }

   # set max upload size
   client_max_body_size 512M;
   fastcgi_buffers 64 4K;

  # Enable gzip but do not remove ETag headers
  gzip on;
  gzip_vary on;
  gzip_comp_level 4;
  gzip_min_length 256;
  gzip_proxied expired no-cache no-store private no_last_modified no_etag 
  auth;
  gzip_types application/atom+xml application/javascript application/json 
  application/l$

  # . . . other code

  location ~ \.php$ {
      include snippets/fastcgi-php.conf;
      fastcgi_pass php-handler;
      #unix:/run/php/php7.2-fpm.sock;
  }
    # Uncomment if your server is build with the ngx_pagespeed module
    # This module is currently not supported.
   #pagespeed off;

      location / {
      rewrite ^ /index.php$request_uri;
  }

  location ~ ^/(?:build|tests|config|lib|3rdparty|templates|data)/ {
      deny all;
  }
  location ~ ^/(?:\.|autotest|occ|issue|indie|db_|console) {
      deny all;
  }

  location ~ 
    ^/(?:index|remote|public|cron|core/ajax/update|status|ocs/v[12]|updater/.+$
    fastcgi_split_path_info ^(.+?\.php)(/.*)$;
    include fastcgi_params;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    fastcgi_param PATH_INFO $fastcgi_path_info;
    fastcgi_param HTTPS on;

    #Avoid sending the security headers twice
    fastcgi_param modHeadersAvailable true;
    fastcgi_param front_controller_active true;
    fastcgi_pass php-handler;
    fastcgi_intercept_errors on;
    fastcgi_request_buffering off;
  }

   location ~ ^/(?:updater|ocs-provider)(?:$|/) {
      try_files $uri/ =404;
      index index.php;
  }

 # Adding the cache control header for js and css files
 # Make sure it is BELOW the PHP block
 location ~ \.(?:css|js|woff|svg|gif)$ {
      try_files $uri /index.php$request_uri;
      add_header Cache-Control "public, max-age=15778463";
      try_files $uri /index.php$request_uri;
      add_header Cache-Control "public, max-age=15778463";
     # Add headers to serve security related headers (It is intended to
     # have those duplicated to the ones above)
     # Before enabling Strict-Transport-Security headers please read into
     # this topic first.
     # add_header Strict-Transport-Security "max-age=15768000; 
    includeSubDomains; prel$
    #
    # WARNING: Only add the preload option once you read about
    # the consequences in https://hstspreload.org/. This option
    # will add the domain to a hardcoded list that is shipped
    # in all major browsers and getting removed from this list
    # could take several months.
    add_header X-Content-Type-Options nosniff;
    add_header X-XSS-Protection "1; mode=block";
    add_header X-Robots-Tag none;
    add_header X-Download-Options noopen;
    add_header X-Permitted-Cross-Domain-Policies none;
    # Optional: Don't log access to assets
    access_log off;
  }

  location ~ \.(?:png|html|ttf|ico|jpg|jpeg)$ {
    try_files $uri /index.php$request_uri;
    # Optional: Don't log access to other assets
    access_log off;
 }

}

Here is the nextcloud config file (/var/www/nextcloud/config/config.php):

<?php
$CONFIG = array (
'instanceid' => 'MYENCRYPTACCOUTNAME',
'passwordsalt' => 'ENCRYPT MY PASSWD',
'secret' => 'SECRET STRING',
'trusted_domains' =>
array (
0 => 'mydomain2.com',
),
'datadirectory' => '/var/www/nextcloud/TTXData',
'dbtype' => 'pgsql',
'version' => '14.0.3.0',
'overwrite.cli.url' => 'https://mydomain2.com',
'dbname' => 'MYDATABASE NAME',
'dbhost' => 'localhost',
'dbport' => '',
'dbtableprefix' => 'oc_',
'dbuser' => 'MYDATABASE USERNAME',
'dbpassword' => 'MyPASSWDDatabase',
'installed' => true,
);

Can anyone tell me where I got the wrong?

BMH