"This ad has already been published or you do not have permission to activate this ad
When I was adding new pages, without knowing I thought "add new" page is a sample page that can be used to make a new page! So I edited that page and renamed it to another page name and put my text into it! then I had this problem:"This ad has already been published or you do not have permission to activate this ad. Please contact the site admin if you are experiencing any issues."
I finally remembered the cause of this error in my case and now I want to fix it. I added a new page named "add new" and the error is gone but it is only a blog page not like the one we had and were able to post an item. which file should I replace to return back to normal?