Security News > 2023 > August > Hotmail email delivery fails after Microsoft misconfigures DNS

Hotmail users worldwide have problems sending emails, with messages flagged as spam or not delivered after Microsoft misconfigured the domain's DNS SPF record.
The email issues began late last night, with users and admins reporting on Reddit, Twitter, and Microsoft forums that their Hotmail emails were failing due to SPF validation errors.
"For Email AdministratorsThis error is related to the Sender Policy Framework. The destination email system's evaluation of the SPF record for the message resulted in an error. Please work with your domain registrar to ensure your SPF records are correctly configured."
After analyzing what was causing email delivery errors, admins noted that Microsoft removed the 'include:spf.
Outlook.com SPF record contains a large list of hosts allowed to send an email for the hotmail.com domain, and with that record missing, any email from those senders will fail SPF checks.
BleepingComputer tested sending an email from an Outlook.com Hotmail account and replicated the problem, with our email going to Gmail's SPAM folder instead due to its SPF record failing.
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