Hello,
To fix the brand
warning, head over to WordPress Dashboard > Rank Math > General Settings > WooCommerce
and choose from any of the available fields to use as your product’s brands.

If you want to use a custom value for your Brands, you can do that by using the following code in your theme’s functions.php file:
// Add Brand for Products.
add_filter( 'rank_math/snippet/rich_snippet_product_entity', function( $entity ) {
$entity['brand'] = 'Rank Math;
return $entity;
});
Replace the “Rank Math” text with your actual brand name then run your website through the Structured Data Testing tool once again.
Hope that helps and please do not hesitate to let us know if you need our assistance with anything else.
I thought that might be the answer too ….but the site does not use Woo commerce.
So what else might be causing that issue?
Hello,
Thank you for contacting Rank Math today.
The product schema expects this value even if you don’t have WooCommerce installed. You will need to use the filter shared by my colleague to pass a custom brand value to your schema from your post type.
Looking forward to helping you. Thank you.
Thank you, I will test and report back to you.
Hi there,
Great! We will be looking forward to your response.
Thank you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.