If you've recently installed Drupal 8, you probably noticed that immediately after you complete the install, you get an error message on the Status Report page about the "Trusted Host Settings". This error message is tricky for most users to remove, since it requires editing the settings.php file (which is read-only), and adding some custom regular expressions to it to match the domain your site is running on. That seems to me like it's impossibly hard for many users to do, so I'm hoping that this process will soon change. In the meantime, I've posted a video with step-by-step instructions for setting up the Trusted Host Settings on a cPanel hosting account.
(This video is part of the Building Websites with Drupal 8 course at DrupalTutor.com.)