This change is part of Microsoft's overall Trustworthy Computing Initiative and was made to further reduce the risk of malicious HTML content reaching our users.
Alternatively, if an user adds your domain or email address to their "contacts" or their "safe-senders list" they will no longer see this notification.
In addition, senders who are on the Return Path Certification list or on a user's "safe sender's" list typically experience links and images within their messages enabled by default. An "allow list" is essentially a "free pass" which allows emails from certain senders to bypass junk email filters and other precautions. You can find out more about our filtering processes here. who helps ensure the legitimacy of certain senders via their Return Path Certification program.
If that doesn't work, try connecting directly to the IPs.
If you are able to connect directly to the IP and not mail.hotmail.com, then it is likely there is an issue with your DNS server.
Microsoft's Smart Screen® technology is designed to provide anti-spam filtering innovations for as well as other Microsoft products like Exchange Server, Microsoft Office Outlook and Windows Live Mail.