for some weeks now, I am experiencing a strange issue: Some post type indices like pages (.../wp-admin/edit.php?post_type=page) or event settings (http://www.musikzentrale.net/wp-admin/admin.php?page=eventon) lead either to a Server Error 500 or a blank screen, whereas others like.../wp-admin/edit.php for posts work as they are supposed to to.
Everything is fine in the frontend, no error messages, missing pages ect. But it makes it hard to get an overview for the pages, to edit a page, I do have to visit it in the frontend, click edit in the admin bar.
Has anyone experienced this in the past and has a smart idea to solve this problem? Your kind help is highly appreciated.
Best regards, Sebastian.