If you’re trying to contact Amazon customers with critical information about their orders, you can avoid bounced emails by including [Important], with brackets, in the subject line of the email. Amazon buyers can opt out of unsolicited messages from sellers, so Amazon recommends this if you’re sending a message to a customer’s email alias outside of the Buyer-Seller Messaging Service in Seller Central. However, this shouldn’t be added to the subject line for all emails. Per Amazon Seller Central:
What sorts of messages are critical to completing an order?
The following messages are considered critical to complete a buyer's order:
- Product customization questions
- Delivery scheduling
- Issues with a shipping address
The following messages are not critical to complete an order:
- Requests for seller feedback or buyer reviews.
- Order, shipment, delivery, or refund confirmations. Amazon already sends these emails.
- Proactive customer service. For example: product manuals, tips for using the product, answers to frequently asked questions, suggestions if something goes wrong.
- Out-of-stock or delay notifications and offers of alternative products. Please cancel the order instead.
Learn more about the feature in Amazon’s Buyer-Seller Messaging FAQ.