Help! I'm blocked at Hotmail! What do I do now?

If you’ve ever found yourself blocked at Outlook.com, the free mail service formerly known as Hotmail, you know that finding out where to start and what to do is confusing. I’ve created the following checklist and tips that any marketer or person sending email can follow to help them get delivered to the inbox.

  1. Check your bounce logs. If none of the mail you are sending is being accepted by Outlook.com or Hotmail or Live.com, check your bounce logs. The Hotmail bounces will include the SMTP error reason code for the block. For a full list of SMTP error codes, go to the end of the page here.
  1. Adhere to the following technical infrastructure guidelines:
  • Set up your DNS. The sending IP address of your mail server should have a valid reverse DNS record using a fully qualified domain name. This will ensure your domain won’t be blocked for appearing to use a dynamic IP address. 
  • Authenticate your email. Hotmail, or Outlook.com, validates incoming domains using SPF and is currently checking DKIM as well. In some cases, publishing an SPF record has moved email from the junk folder to the inbox, indicating that Microsoft places some weight on authentication in their reputation scoring model.
  • Manage connection settings. Do not open more than 500 simultaneous connections to Hotmail and Outlook.com mail servers. Failure to do so will likely result in your mail being deferred and you’ll need to adjust your settings if you expect to get through.
  1. Manage your reputation. Sending history, subscriber complaints and list quality are important measures that Hotmail, Outlook.com and most mailbox providers look at to decide whether or not the email should be blocked or sent to the junk folder.
  • Reduce complaints. Filtering at Hotmail and Outlook.com is often the result of excessive complaints from your subscribers. Ensure you are signed up on the Microsoft Junk Mail Reporting (JMR) program (commonly called a feedback loop) and suppress all complainers from your email list immediately. But don’t just remove the complaints from your list; use that feedback loop data to help you identify why they complained in the first place. Keep track of campaigns that experience a high rate of complaints to help troubleshoot potential problems. Consider such things as content relevance, data source of subscribers and the age and activity of the data generating complaints and make the appropriate adjustments to your program.
  • Sign up for Microsoft’s Smart Network Data Services (SNDS). Microsoft provides valuable data about Hotmail and Outlook.com to help you monitor your IP activity via SNDS. This free service will help identify campaigns resulting in excessive complaints and spam trap hits. Use this information to help identify the root cause of issues and take the appropriate action to correct the problem.
  • Look out for Brightmail filtering. Hotmail and Outlook.com uses the Brightmail anti-spam content filter in their filtering decisions. The Brightmail technology learns what email is spam from all mail received in their spam trap network. If a high volume of your mail is considered suspicious, your IP address could be blocked or bulked. You can check your Brightmail IP reputation and request block removal here.
  • Remove invalid addresses. Manage your list to ensure the removal of invalid accounts (unknown users) and old/inactive subscribers. Don’t be tempted to “pad” your list with these addresses hoping it will make your overall metrics look better. Microsoft and other Mailbox Providers can tell if you do and will often filter your mail into the bulk folder as a result.
  • Send from IPs with a positive reputation. Microsoft wants to see you deploying your mail from IPs with an established sender reputation. A new IP with no reputation does not mean it has a good reputation. As a result, mail sent from new IPs is usually filtered into the bulk folder until a positive reputation is observed. Refer to the following blog for details on how you can build the reputation on a new IP. 
  • Verify your IP reputation. Ensure you regularly check your IP reputation and the various factors causing any decline via senderscore.org. Return Path research has shown that the higher your Sender Score, the better your chances of reaching the inbox. The following illustrates the percentage of mail that landed in the inbox at the top Mailbox Providers in relation to their Sender Score:

  1. Keep your subscribers engaged with your email. Subscriber engagement impacts whether your email will reach the Hotmail or Outlook.com inbox or junk folder. Microsoft has stated they look at the following areas of engagement to decide whether or not to send email to the inbox or spam:
  • Messages read, then deleted
  • Messages deleted without being read
  • Messages replied to
  • Frequency of receiving and reading a message from a source

While you may not have insight into these metrics, you should be tracking opens, clicks, conversions, web activity, etc. on your end. If your subscribers don’t register any activity based on your internal metrics, chances are they aren’t performing for Microsoft either.

Help keep subscribers engaged by setting the proper expectations up front regarding the type and frequency of email the subscriber will receive. Deliver on what you promised with email that is relevant to them and they can easily recognize is coming from you.

  1. Get Certified. Wow, that’s a lot to keep track of! The good news is Microsoft domains like Hotmail and Outlook.com use the Return Path Certified whitelist. By having a third party like Return Path accredit your sending practices, Microsoft can deliver your email to the inbox at Hotmail and Outlook.com, and with images enabled. Acceptance into that program will positively impact delivery.

Do you have other tips for reaching the Outlook.com and Hotmail inbox? Please feel free to share!