Hikashop - Message from an Order

-- HikaShop version -- : 6.3.0
-- Joomla version -- : 5.4.2

Hello

I'm validating transactional emails for Hikashop, and one isn't working. When a user makes a purchase, they can access the order details page, which they can also access from their user profile. On that page, they have the option to send a message or ask a question by clicking the "Contact us about your order" button. When they click the button, a form opens to send a message. I assume the message is directed to the seller of the purchased order, but the email never arrives. I've checked the spam folders and run several tests, but it's still not getting through.

Could you explain how to validate this email and how to fix it?

Thanks!