Thus, starting March 1, 2026, Exchange Online will begin phasing out Basic authentication for sending emails via SMTP AUTH. At first, fewer attempts will be blocked, but by April 30, 2026, this ...

Microsoft warned today that it will permanently turn off Exchange Online basic authentication starting early January 2023 to improve security.

Basic Auth is an outdated authentication method where a user's credentials are sent in plaintext or base64 encoded form with every request to a server. It lacks modern security features like MFA ...