All free email providers have begun executing a stricter email policy that potentially could result in your newsletters landing up in the spam folder or being returned to you as bounced mail.
If you're already sending through Emailbrain, you already enjoy a much higher success rate at having your emails delivered – because we ensure optimal deliverability with feedback loops and we're a member of ReturnPath.
However, if you send your emails from a personal free email address, your newsletter send will look fraudulent—even if it is not—due to the changes implemented by free email providers.
These changes will affect receiving servers that comply with DMARC policies, including Gmail, Hotmail, Yahoo, AOL and others.
Domain-based Message Authentication, Reporting and Conformance, or DMARC validation for short, is used by receiving inboxes.