I’m trying to delete a post directly in the post, which isn’t working, and then right click on the list of posts to delete and still doesn’t delete. I’m getting this error message at the top for each “Internal server error, cannot delete post. An unexpected error occurred, please try again.”
Are you self-hosting it? If yes, have you checked the server logs?
Edit: found your site in your old post. That looks like a Ghost(Pro) site. The issue with an “Internal server error” is that it’s on the server − that is not something you (or us) can diagnose from the outside, realistically.
So, the best course of action is a quick email to Ghost(Pro) at support@ghost.org. Though, they’ll only be back by Monday, I am afraid.