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).We may not accept email from senders who fail a reverse-DNS lookup.
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.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.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.
You can find the current list of our MTAs by querying "nslookup –q=mx hotmail.com" from a command prompt (this should work in a variety of Operating Systems).
Currently, the addresses for these servers are mx1.hotmail.com, mx2.hotmail.com, mx3.and mx4.
These services have been tailored for senders and for ISPs.
To learn more about the Sender and ISP Services, go here.
However, submitting this information does not guarantee that any message you send to users of the services will be delivered.