I installed wordpress 4.7.3. After that I created one "Test" category. After that I created one post and assigned to that "Test" category. Then I go to front end, in the right menu and clicked on "Test" category.
Then it shows page with text "OOPS! THAT PAGE CAN’T BE FOUND." "It looks like nothing was found at this location. Maybe try a search?"
Using default wordpress theme "Twenty Seventeen".
Please why it is not showing category page with post assigned to that category?