About php : File-not-found-after-changing-url-in-virtualhost-for-my-drupal-site

I am trying to add a dev site to make a copy of my Drupal live site, and change URLs for both production site and development site instead of having my ip address in the URLs. So far, I have done:

1. making directory for dev site and imported backup db
2. adding a new <virtualhost *:80> for dev site in drupal.conf
3. changing ServerName and ServerAlias to the new URLs I wish to change
4. drush cr and restart httpd then enabled it
5. When I typed the new URL that I changed for the production site on browser, I get “File not found.” error. Can anyone tell me what am I missing? Do I need to change anything in settings.php? Thank you in advance