When someone marks your email as spam, they’re essentially blacklisting you. This makes it extremely tough to reach them in the future since your emails will be automatically filtered out.
Unfortunately, sometimes even CAN-SPAM compliant emails wind up in the junk folder. To avoid this, it’s important to ask your recipients to whitelist your emails.
A whitelist works the opposite way a blacklist does: By adding the sender’s email address to the person’s contact or address book, your recipients will mark your emails as trusted and important instead of as junk.
One way to ask subscribers to add your email to their address book? Ask them in your thank-you message that pops up whenever a visitor subscribes to your list. If you skip this crucial step, many readers could miss your messages even though they actually want to hear from you.