"wp-admin/post.php not found" when updating certain post

Hi there,

I checked 10 different topics before posting this question, but I couldn’t find an answer. When I try to update a certain post on my site, I get a “404 wp-admin/post.php not found” error. All other posts can be updated. I even tried updating the post without changing anything in it, but that didn’t work either. No idea what’s causing the error.

Post.php is naturally in place, and it’s even used to edit the post, but it simply cannot be updated. I haven’t changed anything lately.

All suggestions would be highly appreciated!

Thanks