What type of message should be analyzed for attachments to identify delivery issues?

Analyzing all email messages is crucial for identifying delivery issues, particularly because attachments can be a common vector for problems. Attachments may alter the way emails are processed through security filters, which can lead to delivery failures, increased likelihood of being flagged as spam, or other issues.

By examining all types of email messages—including those with text, HTML, and spam characteristics—it's easier to pinpoint patterns that could indicate why certain messages aren’t getting delivered properly. Such comprehensive analysis allows for better troubleshooting and enhances the overall security posture by ensuring that all potential issues are addressed.

In contrast, focusing solely on specific types of emails, like just HTML messages or spam messages, would limit the scope of analysis. Text messages are also not a primary concern in traditional email delivery issues since they typically don't contain attachments that could interfere with email systems. Therefore, the comprehensive approach of analyzing all email messages helps in thoroughly evaluating and resolving delivery issues related to attachments.