I added the Responsive Filemanger to my CKEditor on my side which has Drupal 7 as CMS. But when I try to add an image or something like this, it returns the relative path and not the absolute path. For example, when the picture is located in "/sites/default/files/picture.jpeg" it should return the whole path and not just "picture.jpeg" because otherwise, it won't display the picture.
So I found an answer for my problem here https://github.com/trippo/ResponsiveFilemanager/issues/241