How Do I fix untrusted domain on NextCloud?

When I go to my setup domain for NExtcloud, this is what I get.

Access through untrusted domain
Please contact your administrator. If you are an administrator, edit the "trusted_domains" setting in config/config.php like the example in config.sample.php.

Further information how to configure this can be found in the documentation. (See Below)

'Trusted domains
All URLs used to access your Nextcloud server must be whitelisted in your config.php file, under the trusted_domains setting. Users are allowed to log into Nextcloud only when they point their browsers to a URL that is listed in the trusted_domains setting. This is not a list of allowed client-side domains or IP addresses. You may use IP addresses and domain names. A typical configuration looks like this:

'trusted_domains' =>
array (
0 => 'localhost',
1 => 'server1.example.com',
2 => '192.168.1.50',
3 => '[fe80::1:50]',
),
Note:

The loopback address, 127.0.0.1, is automatically whitelisted, so as long as you have access to the physical server you can always log in. In the event that a load balancer is in place there will be no issues as long as it sends the correct X-Forwarded-Host header. When a user tries a URL that is not whitelisted the following error appears:"