front end add category to new post

It looks like you’re trying to use the default Post post type’s Category taxonomy with your custom post type movies.

$post_info = array(
  'post_type'     => 'movies', // custom post type here
  'post_status'   => 'pending',
  'post_title'    => esc_attr(strip_tags($_POST['title'])),
  'post_content'  => esc_attr(strip_tags($_POST['overview'])),
  'post_category' => $category, // categories are by default only for Post post type
);

Have you already added such code to your site, which allows you to use the default Category taxonomy with your custom post type? If not, have a look here on how to do it, tags & categories with custom post type

If you have registered a custom taxonomy for your movies post type, then you should use tax_input in your $post_info array. Like so,

$post_info = array(
  'post_type'     => 'movies',
  'post_status'   => 'pending',
  'post_title'    => esc_attr(strip_tags($_POST['title'])),
  'post_content'  => esc_attr(strip_tags($_POST['overview'])),
  'tax_input'     => array(
    'some_custom_taxonomy' => $category
  ),
);