How do I redirect to the login page?
There are a couple of modules that do this

Redirect 403 to Login: https://www.drupal.org/project/r4032login
Anonymous Login: https://www.drupal.org/project/anonymous_login
You could probably also do it with the Rules module
Simplest: You can also go to admin/config/system/site-information and set the &quot;Default 403 (access denied) page&quot; to &quot;/user/login&quot;

This page was old, but looked like it had been updated along the way for Drupal 8.