So I installed shoreditch on a drupal 7 civicrm. I can enable on the extensions page but on /civicrm/admin/setting/url?reset=1 I see no option to enable the shoreditch them. I can add the custom-civicrm.css there but not the shoreditch option I see on another (Wordpress) installation. This is on a civicrm 5.6.0. Any thoughts?
Frequent reason for that error: Double-check, that your URL resource entries are correct! At best, you should use the URL variables, such as e.g.:
In Drupal, install the Shoredich theme extension. Make sure you use the latest one! Check the extension documentation.
Basically in Drupal you choose the Seven theme as the CiviCRM admin theme.
Then, back over in CiviCRM in Resource URLs, you set the CSS to use the Shoreditch CSS.
Should then work as intended.
Had that once before, as @Laryn mentioned clearing my caches helped!