Why is my email deliverability to Microsoft Outlook and Hotmail so bad?
Summary
What email marketers say14Marketer opinions
Marketer from Email Geeks shares that Microsoft has been more problematic than usual, starting around October 2019. Their support usually cites unusual activity or SmartScreen filter recommendations.
Marketer from Email Geeks mentions if an IP is blocked by Microsoft (visible in SNDS), stopping all traffic to Microsoft domains for 2-3 days, then restarting with small amounts of traffic to engaged recipients is usually effective.
Email marketer from EmailToolTester shares that using a shared IP address can impact deliverability if other senders on the same IP are engaging in practices that harm the IP's reputation. Switching to a dedicated IP can give you more control over your reputation.
Email marketer from SendPulse shares that Microsoft prioritizes senders who properly authenticate their emails using SPF, DKIM, and DMARC. Implementing these authentication methods can improve deliverability by verifying your identity.
Marketer from Email Geeks explains that Microsoft is extremely sensitive to volume changes and a single spike can impact delivery for weeks.
Email marketer from Mailjet explains that Microsoft is highly sensitive to complaint rates. If a significant percentage of recipients mark your emails as spam, your deliverability will suffer. Monitoring and managing your complaint rate is crucial.
Email marketer from Litmus explains that the content of your emails can impact deliverability. Using spam trigger words, excessive links, or poorly formatted HTML can increase the likelihood of your emails being filtered as spam.
Email marketer from HubSpot explains that warming up your IP is important for deliverability. You need to gradually increase the volume of emails your sending from your IP over time to build a solid reputation.
Email marketer from Email Marketing Forum shares that inconsistent sending volumes can trigger spam filters. Sudden spikes in email volume, especially if you're normally sending low volume or have a new IP, can lead to Microsoft flagging your emails as spam.
Email marketer from Neil Patel Digital explains that your domain reputation is a critical factor. Microsoft heavily relies on sender reputation when filtering emails, so a poor reputation can significantly impact deliverability to Outlook and Hotmail addresses.
Email marketer from StackOverflow shares that user engagement is very important for deliverability. You need to try and encourage opens/clicks and get your users to move you from the junk folder or add to safe senders list.
Marketer from Email Geeks says that if you can't produce steady volumes, you should stick to shared IPs because Microsoft has a high sensitivity to variations in volume.
Email marketer from ActiveCampaign shares that doing A/B Testing to improve deliverability, is an effective way of discovering what your user base likes, and to optimise subject lines and email content.
Email marketer from Reddit shares that poor list hygiene is a major cause of deliverability issues. Sending emails to outdated, invalid, or unengaged email addresses leads to bounces and spam complaints, which negatively impact your sender reputation.
What the experts say4Expert opinions
Expert from Word to the Wise explains that Microsoft places a heavy emphasis on sender reputation. This includes factors like IP address reputation, domain reputation, and user engagement. If these are low, your deliverability to Outlook/Hotmail will be impacted.
Expert from Word to the Wise recommends actively monitoring blocklists, as a listing on a major blocklist can severely impact your deliverability to all email providers, including Microsoft. Regularly check your IP and domain against popular blocklists.
Expert from Email Geeks says that Outlook.com and Office365 do not behave similarly with respect to deliverability.
Expert from Spam Resource explains that Hotmail heavily relies on user engagement metrics to determine inbox placement. Low open rates, click-through rates, and high complaint rates can signal to Hotmail that your emails are unwanted, leading to deliverability issues.
What the documentation says4Technical articles
Documentation from Microsoft Support explains that they implement strict throttling policies to protect their users from spam. Sending large volumes of email in a short period, especially from new IPs or domains, can trigger throttling and impact deliverability.
Documentation from RFC explains that having a properly configured reverse DNS record (PTR record) that matches your sending IP address to your domain name is very important for deliverability. Ensure your rDNS record is properly setup.
Documentation from Microsoft provides the Sender Network Data Services (SNDS) tool, which allows you to monitor your IP reputation and identify potential issues affecting deliverability to Microsoft domains. Regularly checking SNDS can help you proactively address problems.
Documentation from Microsoft explains the importance of implementing a Feedback Loop (FBL) to receive reports of spam complaints from their users. This allows you to identify and remove subscribers who are marking your emails as spam.