Free email providers such as Yahoo, AOL, and Gmail have changed their DMARC authentication policies, which affects the delivery of emails sent through all email service providers, including HubSpot. Learn more about how DMARC works.
To protect your email sending reputation, the marketing email tool won't include user emails from free providers in the From address dropdown menu in the email editor. It's also not possible to add an email address from a free provider within the email editor.
Please note: effective January 31, 2019, all from addresses used to send marketing emails must be verified.