This question was asked before, and marked answered at: Unable to upload or view files through the CKEditor
but the adjustment recommended did not solve the problem for me.
After upgrading to CiviCRM 5.22.1, I am no longer able to upload image files when working on defining a mailing. With previous versions of CiviCRM I could Upload an image using the dialog box Upload Tab that appears when clicking the image icon.
On the 1. Define Mailing tab on ,,, /wp-admin/admin.php?page=CiviCRM&q=civicrm%2Fa%2F#/mailing/151 clicking the image icon opens a dialog box titled: Image Properties It has 4 tabs: | Image Info | Link | Upload | Advanced
Selecting the Upload Tab shows Choose File:
I can enter an image file to import. But when I click the button "Send it to the Server"