Microsoft has announced new email sender requirements aimed at enhancing email authentication and deliverability for high-volume senders. These guidelines are particularly relevant for hotel marketers who rely on Cendyn CRM application to reach their customers effectively.

Key Changes and Requirements

SPF Authentication

Ensure your messages pass SPF (Sender Policy Framework) checks. Your domain's DNS record should accurately list authorized IP addresses/hosts.

DKIM Authentication

Sign your messages using DomainKeys Identified Mail (DKIM) to validate email integrity and authenticity.

DMARC Policy

Publish a DMARC (Domain-based Message Authentication, Reporting, and Conformance) record with at least a policy of p=none. Ensure alignment with either SPF or DKIM, preferably both.

Alignment Requirement

Ensure message alignment, meaning the SPF or DKIM authentication domains must match the "From" domain.

Compliance Consequences

Messages failing to meet these standards will be directed to the junk folder, with potential for outright rejection in the future.

Additional Recommendations for Email Hygiene

• Valid Sender Addresses: Ensure the "From" or "Reply-To" address is valid, reflects the true sending domain, and can receive replies.
• Functional Unsubscribe Links: Provide an easy, clearly visible way for recipients to opt out of further messages.
• List Hygiene & Bounce Management: Regularly remove invalid addresses to reduce spam complaints, bounces, and wasted messages.
• Transparent Mailing Practices: Use accurate subject lines, avoid deceptive headers, and ensure recipients have consented to receive your messages.

Enforcement Timeline

Starting May 5th, 2025, Outlook will begin routing messages from high-volume non-compliant domains to the junk folder, giving senders an opportunity to address any outstanding issues. Future non-compliant messages may be rejected to further protect users.

Next Steps for Hotel Marketers

• Audit Your DNS Records: Review and update your SPF, DKIM, and DMARC records to ensure compliance.
• Keep an eye on the Microsoft Blog for updated content. 

By adhering to these new guidelines, hotel marketers can ensure their messages reach their intended audience while maintaining trust and security in the digital communication landscape. Should you have any questions regarding your domain's compliance, reach out to our Global Support Team with a ticket.

For more detailed information, visit the Microsoft Defender for Office 365 Blog.