add_action('init','yoursite_init');
function yoursite_init() {
global $wp_rewrite;
//add rewrite rule.
add_rewrite_rule("author/([^/]+)/page/?([0-9]{1,})/?$",'index.php?author_name=$matches[1]&paged=$matches[2]','top');
add_rewrite_rule("(.+?)/page/?([0-9]{1,})/?$",'index.php?category_name=$matches[1]&paged=$matches[2]','top');
$wp_rewrite->flush_rules(false);
}
Adding this to my functions.php solved it for me.