In Drupal 8, I got the following error message when I install the backup of the live website on my local development machine.

The provided host name is not valid for this server.

Solution

The cause of this issue is I enabled Trusted Host settings on the live website. Now that I brink it back to my local development environment, it doesn't recognized the domain that I set earlier.

To resolve this issue, I edit the .../sites/default/settings.php and add '^localhost$', to the $settings['trusted_host_patterns'] variable as follows:

$settings['trusted_host_patterns'] = array(
  '^localhost$',
  '^example\.com$',
  '^.+\.example\.com$',
  '^.+\.jsdelivr\.net$',
  '^.+\.cloudflare\.com$',
);