If you are having email deliverability issues with Hotmail, you are not alone. Outside of Yahoo, Hotmail seems to be the most problematic domain, especially for new senders. Hotmail delivery can be very challenging and Hotmail is notorious for vaporizing your email without warning. So this brings up two issues.
- How do you know if your mail is landing in the spam box or, worse, being vaporized?
- If you find a delivery problem, how do you correct it?
Detecting deliverability problems with Hotmail
The first place to look is in your logs. If you are seeing a large number of deferrals or failures to Hotmail, the Hotmail server responses in the log entries will give you an idea of what the problem is. It may be that you need to throttle back delivery to Hotmail, or make some other configuration change on your MTA or in DNS.
Next consider setting up a Hotmail account or two and put the addresses on your mailing list. That way you can periodically log into your Hotmail account and see if your messages are making it to the inbox. (While you are at it – check your rendering.) This is easy to do yourself, however there are mailbox monitoring services available that will do this for you (for a fee) and will work with many of the important ISPs.
Correcting Hotmail Issues
Hotmail is also notorious for penalizing mail from unfamiliar IP addresses. If you are sending email from an IP that has not had much use recently for mail, this may be the case. As you send more mail over the IP, and Hotmail becomes familiar with it, more of your mail should get through.
Another option is to sign up for a whitelisting or accreditation service. SocketLabs has partnerships with the major providers of these services and can help you select one to suit your needs.
Finally, here is a great resource from Microsoft for troubleshooting and overcoming Hotmail delivery issues, including a support contact: