We have identified an issue that may cause some customers to receive bounce-back messages when sending emails to Outlook.com, Hotmail.com, or Live.com email addresses.
This issue is typically caused by missing, incomplete, or incorrectly configured email authentication records, including SPF, DKIM, and DMARC.

Microsoft has recently strengthened its email security requirements and may reject messages from domains that do not have valid email authentication configured. As a result, email delivery may fail even if messages were previously being delivered successfully.

To resolve this issue, please review your domain’s DNS configuration and ensure that valid SPF, DKIM, and DMARC records are in place and correctly configured.

Once these records have been implemented, email delivery to Microsoft-hosted email addresses should return to normal.