Trusted host setting warning in Drupal 8
After a new installation of Drupal a warning message can appear in your configuration screen concerning trusted host settings.
To address this issue go to the settings.php file in your website directory of Drupal.
The location of the settings.php file should be at:
Drupal[root] \ sites \ [website name] \ settings.php
Change or add the following to eliminate the warning in the settings.php file.
$settings['trusted_host_patterns'] = [
Additional changes can be added for sub domains.