404 Page Not Found on /Page/2/ on Tag Page

Nevermind. I forgot to add this in my functions.php. I will leave the answer here so it may help others.

//Tag pagination pages
function wpd_custom_types_on_tag_archives( $query ){
    if( $query->is_tag() && $query->is_main_query() ){
        $query->set( 'post_type', array( 'portal' ) );
    }
}
add_action( 'pre_get_posts', 'wpd_custom_types_on_tag_archives' );