1. High Bounce Rates A high bounce rate is a clear indicator of inaccurate or outdated email addresses. If a significant number of your emails are bouncing back, it's time to clean your email list.
2. Low Engagement Rates Low open and click-through rates can indicate that your emails are not reaching the right audience. This could be due to incomplete or outdated data.
3. Spam Complaints If you're receiving a lot of spam complaints, it could be a sign that you're sending emails to people who did not opt-in, which often happens due to poor data quality.