Clean URLs caused site to break? I'm installing a new Drupal site using Red Hat... Getting Clean URLs to work was a pain in the you-know-what. I followed all the steps in the official drupal.org helpguide, but ended up needing extra help for a guide specific to RHEL users here: https://www.tecmint.com/install-drupal-in-centos-rhel-fedora/

I went into my httpd.conf file and made AllowOveride All as shown here: https://www.tecmint.com/wp-content/uploads/2013/07/Enable-Clean-URL-in-Drupal.png

I then fixed all of my directory issues in .htaccess (because my .htaccess file is in sites/web), and then all my admin links work perfectly. So Clean URLs is definitely enabled, but the issue now is the site is broken.



This was probably caused by enabling Clean URLs through the httpd.conf issue, but I'm not sure. I ran drush cr and it did nothing. Help?
As leymannx and Kevin mention it is probably a misconfigured tmp/files directory

Uncheck aggregate css is something that you would not want on your live site as the performance will suffer.

Check in Reports > status report (/admin/reports/status) and try to fix or report on the errors that you see.  

Also go into configuration > media > file system (/admin/config/media/file-system) and correct any file system problems reported when saving the settings.

The most probable cause of what you are seeing is wrong permissions.

There is a lot of guides on the net about setting those permissions. 
You can start from the official guide on the subject or on one support thread that started as a drupal 7 thread but has Drupal 8 answers.