- Bounce Rate: A high bounce rate indicates that many of your emails are not being delivered, which can harm your reputation. - Spam Complaints: If recipients frequently mark your emails as spam, it will negatively affect your reputation. - Engagement: Low open and click-through rates suggest that recipients are not interested in your content, which can also hurt your reputation. - Spam Traps: Sending emails to spam traps can severely damage your reputation. Spam traps are email addresses that are not used for communication but are monitored to catch spammers. - Blacklists: If your IP address or domain is listed on a blacklist, your emails are more likely to be blocked or sent to spam folders.