I created a post and assigned it a category and tag also. The post is displaying on the main post page. But the problem is when I go to the specific category page the post is not showing.

For information, I am using the theme "Smarty 3.3" to build a website for a school. My post URL looks like "http://localhost/myschool/2019/12/22/post-name". And the category URL is like "http://localhost/myschool/category/news/"

I must add, the post is not even showing when search by category or tag name.