Attachment box in post types without images which are shown on the frontend

Hi!

after a virus and restoring a backup, I couldnt see attachmant boxes in my post types at all. I solve the problem following the guide here. Now I see the boxes in my post types where I can add images, but they are empty, without the images which are shown on the frontend. How do I link them again?

Hope you can help, thanks for your help.