A complaint occurs when recipients indicate that your email is spam. They can file a spam complaint against the sender two different ways. The first: every email client has a spam complaint button. For example, in gmail, a user can flag an email as spam which reports the sender’s IP address and email to Google’s servers and eventually block or lower the reputation of the sender depending on how many other users flag the email as spam. The second: MNB provides a small complaint link included with every email sent from our servers. If the recipient clicks this, MNB will record this as part of your Acceptable Spam Report Rate.