Email marketing is a highly effective channel, offering substantial returns on investment, but its success hinges on maintaining a high domain sender score, which reflects a sender's trustworthiness to email providers. A low sender score can lead to emails being undelivered or marked as spam, thereby diminishing engagement and revenue. The sender score, akin to a credit score, is determined by multiple factors, including complaints, blacklists, engagement rates, and email list quality. To avoid a poor score, it is crucial to maintain a high-quality email list, verify addresses, and ensure consistent and targeted communication. Continuous improvement in list hygiene, content quality, and engagement metrics can enhance sender scores, allowing marketers to reach their intended audience effectively. Understanding and managing these factors is essential for sustaining email marketing success and keeping communications out of spam folders.