When sending mass emails, contacts have to be subscribed to an email list. When creating an email list, you must supply the list name (internal), the website/domain (your website), and the list description.

Important: The list URL should be your company’s domain. If email recipients mark emails as spam/unsubscribe your domain reputation can be flagged. A bad domain reputation can damage email deliverability and can hurt website rankings. We recommend only mass emailing people who are active customers. Mass emailing should not be used in prospecting sequences/automations.

You can register your company’s domain with Google Search Console to monitor your company’s domain reputation.