Site not working after plugin

Hey, i have transfered some postings (core) to a custom post type. Now the categorie (core) always shows me the number of post, that they were there before, even when i moves all of them to the new custom post type.

Now when i try to post an article (core) to any categorie, it is not shown on the frontend. I think this plugin damaged my site :-(. Can anyone help?

Best