Microsoft Outlook rolls out stricter email authentication requirements for high-volume senders to enhance security
Microsoft Outlook.com (which includes hotmail.com, live.com, and outlook.com) is implementing new email authentication procedures in an attempt to improve email security and preserve customer confidence. These modifications, which came into effect on May 5, 2025, are intended especially for high-volume senders, or those who send more than 5,000 emails every day.