Content Analysis: The test checks for spammy words and phrases, excessive use of punctuation, and other content-related red flags. Sender Reputation: It evaluates the sender's domain and IP address for any history of spam complaints or blacklisting. Authentication: It verifies the use of email authentication protocols like DKIM, SPF, and DMARC. Technical Factors: The test examines the email's HTML code, image-to-text ratio, and other technical aspects.