Return Path has a certification service that certain providers use as a signal to the “legitimacy” of the sender (don’t know if that was the best phrasing...).

Return Path has a certification service that certain providers use as a signal to the “legitimacy” of the sender (don’t know if that was the best phrasing...). https://returnpath.com/solutions/email-deliverability-optimization/ip-certification/ https://returnpath.com/solutions/email-deliverability-optimi...