I'm trying to edit the system workflow message "Events - Registration Confirmation and Receipt (on-line)". When I edit it and hit save, it just reloads to a blank (new) message template. No changes are saved. The message is currently set to the default version.
I'm on Drupal 7, CiviCRM 4.7.22. It's a copy of our live site, where I can indeed make edits. Is there some kind of file permission I could have missed when I duplicated the site? I have all the error and logging turned on for this site, but I don't see an error on the page or the Drupal log.