Missing field “aggregateRating”

Hello,

Thank you for contacting Rank Math and sorry for any inconvenience that might have been caused due to that.

Could you share with us the URL you are getting this issue.

If it is a product URL, Rank Math takes the schema data from your product pages automatically and turns it into Schema-ready content. Likewise, the aggregateRating and review fields are taken from your actual product reviews that your buyers/customers leave on your products.

Please acquire some reviews and ratings to get rid of the aggregateRating and review warnings.

Hope that helps and please do not hesitate to let us know if you need our assistance with anything else.

Hello,

To solve the reviews issue there, you will need to allow users to publish their own reviews and acquire at least one from them. I see you have an author review, but it doesn’t count for that Schema field. If you are not able to get them, you can just ignore it since it won’t affect your SEO.

About the ISBN, if you are using WooCommerce for the products, you can just add the following code in the functions.php file (at the end) and set the ISBN in the SKU field. If you are not using WooCommerce, you will need to modify the code to fit your needs:

add_filter( 'rank_math/snippet/rich_snippet_product_entity', function( $entity ) {
    if(is_product()){
        global $product;
	$sku = $product->get_sku();
        $entity['isbn'] = $sku;
    }
    return $entity;
});

Looking forward to help you.