Hello When clicking on manage categories and then clicking a sub category. None of the data is loading up in the forms as seen below
This seems to be some kind of restriction on your server, rejecting the Ajax request.
This post can help:
Has any changes been made to your server environment, specifically related to apache, and mod_security?
Something to try, and determine if it is specifically AJAX issue, is to grab those urls from the console, and remove the isAjax=true form the end, and see what happens if you request them directly,