Smart Screen® email filters are influenced by a number of factors related to the sending IP, domain, authentication, list accuracy, complaint rates, content and more.
Of these, one of the principal factors in driving down a sender's reputation and deliverability is their junk email complaint rate.
Avoid using scripting languages as they may be removed from your message.
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.Some of the deliverability issues are the result of sender-based software configurations.If you are running anti-virus software on your firewall or SMTP server, check for the setting "Internet Email Auto Protect" or "Internet Email Protection." If this setting is enabled, disable it and try sending a test message to our servers again. If you are unable to connect, then attempt to telnet over port 25 directly to our email servers (MTAs).IPs not previously used to send email typically don't have any reputation built up in our systems.
As a result, emails from new IPs are more likely to experience deliverability issues.This section provides troubleshooting information for senders who are having trouble reaching users by email.If you are an user looking for support with your account, please visit our end user support page.If the domain has a good sending reputation new IPs may experience a faster ramp up time.A new IP can expect to be fully ramped within a couple of weeks or sooner depending on volume, list accuracy and as long as their junk email complaint rates are kept at a minimum.We may not accept email from senders who fail a reverse-DNS lookup.