Home page still loading using Public IP from port forwarding

Nextcloud version 14.0.1
Operating system and version Ubuntu 16.04
Apache 2.4.18 (ubuntu)
PHP version 7.0

The issue:
I have nextcloud installed on my local server with my local ip address. and then I try to use public address to my nextcloud with my isp public address. I’m using a router to setting port forwarding to forward public ip to nextcloud private ip address.
Some of my

Is this the first time you’ve seen this error? Y

The output of your Nextcloud log in Admin > Logging:

keep loading after login (cannot upload file)

The output of your config.php file in /var/www/nextcloud/config/config.php:

$CONFIG = array (
  'instanceid' => 'xxxxxxx',
  'passwordsalt' => 'xxxxxxxxxxxxxxxxxxxx',
  'secret' => 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
  'trusted_domains' =>
  array (
    0 => 'private_ip',
    1 => 'public_ip',
  'datadirectory' => '/var/www/nextcloud/data',
  'dbtype' => 'mysql',
  'version' => '',
  'overwrite.cli.url' => 'http://private_ip/nextcloud',
  'dbname' => 'xxxxxxxxx',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'xxx',
  'dbuser' => 'xxxxxx',
  'dbpassword' => 'xxxxx',
  'installed' => true,

The output of your Apache/nginx/system log in /var/log/____:

[Fri Nov 16 10:57:27.138924 2018] [ssl:warn] [pid 71953] AH01909: server certificate does NOT include an ID which matches the server name
[Fri Nov 16 10:57:27.141280 2018] [mpm_prefork:notice] [pid 71953] AH00163: Apache/2.4.18 (Ubuntu) OpenSSL/1.0.2g configured -- resuming normal operations
[Fri Nov 16 10:57:27.141299 2018] [core:notice] [pid 71953] AH00094: Command line: '/usr/sbin/apache2'