Get control over your email deliverability and sender reputation
If you use any email tracking tool, your emails include links to a domain that you don’t control and that can negatively affect your sender score and email deliverability (other users can use an email tracker for sending spam
).
That's why your one-to-one emails can end up in your recipient's spam folder 
You can exclude this negative impact on the deliverability of your tracking emails if you set up your custom tracking domain. Learn how to do it.