So you’ve created a custom post type with a custom slug and you’ve added some content and viewed the post only to find a 404 Page Not Found Error page. This is because although you registered your new post type WordPress doesn’t know how to handle it yet.
Simply go to settings>permalinks and choose a permalink structure if you haven’t done so already. Once done click “save changes” and make any changes to .htaccess if prompted to do so. Now view you custom post again and all should be right with the world.