# Drops

*Email Deliverability*. The removal of an email message to a specific recipient to protect the sender's [reputation][ers].

Some [email service providers (ESPs)][esp] maintain email lists that track bounces, spam reports, and unsubscribes for each user. If you try to send a message to an email address exists on one of these lists, the ESP drops the message.

[ers]: /docs/sendgrid/glossary/email-reputation-score

[esp]: /docs/sendgrid/glossary/email-service-provider