Starting May 5, 2025, Microsoft enforces strict sender requirements. Emails from domains sending over 5,000 messages per day must pass SPF, DKIM, and DMARC checks.—or face the 550 5.7.15 Access Denied error.

The post Microsoft Sender Requirements Enforced — How to Avoid 550 5.7.15 Rejections appeared first on Security Boulevard.

Ahona Rudra

Source: Security Boulevard
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