I have a site I’ve recently migrated to a new server. Everything is mostly looking okay, except on existing posts: when we go back to edit a post, and edit media attachments within it, the “Edit Original” and “Replace” buttons are missing.
The file URLs are all correct, and on the server, permissions of both the files and the parent directories are the same on both servers.
If I add a new image to an old post, it works fine; it’s just trying to access the buttons on the existing images that’s a problem.
Working, old server:
http://i.stack.imgur.com/K8Dwx.png
Not working, new server:
http://i.stack.imgur.com/DMHEB.png
Any ideas?
Be sure that you’ve correct permissions set on your webserver.
https://codex.wordpress.org/Changing_File_Permissions
If permissions are set incorrectly WordPress is throwing weird problems like this one, another symptom is that you can’t just install plugins. (it’ll ask you for FTP details)