Autodetecting variables for URL variables
If those tokens aren't working for you, it's OK to use the absolute URL or path without the token instead. Would that solve the problem for you?

https://www.example.org/wp-content/plugins/files/civicrm/


There seem to have been a few questions about this recently. I haven't run into it myself, but got an impression this may relate to symlinks in the webserver path.

There has been a bit of work recently regarding miscalculation of [civicrm.files] values - contributing information to these linked discussions may help to get the problem resolved: 


CRM-20609: File URL when CiviCRM detects Drupal doesn't match path set by [civicrm.files]
CRM-19303: CKEditor configuration can't be edited on a Drupal multisite installation
Lots of discussion of this in PR9458