Identifying slow email delivery involves monitoring various metrics and using specialized tools. Here are some methods to diagnose the issue:
Email Analytics: Regularly check analytics for delayed email opens and click-through rates. If there's a sudden drop, it could indicate delivery issues. Feedback Loops: Set up feedback loops with ISPs to receive notifications when emails are marked as spam or face delivery issues. SMTP Logs: Analyze SMTP logs to identify any bottlenecks or errors in the email delivery process. Delivery Reports: Use delivery reports to track the time taken for emails to reach recipients.