by Beverly Jan 12, 2018

If you are wondering why your statistics are not good or at the same level as before when sending to Microsoft email addresses, we have a few tips that will help you fix this.

As an account owner, recently you may have noticed an increase in complaint rates and a reduction in open rates generated from your sending to Microsoft email addresses (,,,, etc.).

What is going on?

Microsoft and Return Path have lowered the complaint threshold for IPs. We are noticing more mitigation load from Microsoft over the last couple of months. Microsoft has apparently changed and improved its email service and infrastructure (migrated to the same back-end as Office 365 which is an improved, more modern solution).

Buttons have been added to Microsoft mobile clients to mark emails as junk or spam. With more emails being opened on mobile devices than ever, it is likely having an impact on your complaint rate from Microsoft.

Previously, Microsoft users who determined email to be spam by moving the mail to the bulk/junk folder were not signaling Email Service Providers like Elastic Email that the mail was not wanted. They have now implemented this feature for both their web interfaces. Even if you are connecting via IMAP clients like Microsoft Outlook.

What does this mean?

Microsoft filters are more strict causing the increase in rejections and bounces. Similar to what Gmail has been doing for years. If you have had trouble in the past inboxing to Gmail, you likely will experience similar patterns with Microsoft. If this is you, ask yourself what you have learned from dealing with Gmail’s changes and try to apply them now with Microsoft’s changes.

Microsoft seems to be doing more "silent rejections". They initially accept emails, but then the mail is not visible in the inbox.

Contact engagement and user interaction are more relevant than ever. Pay attention to your results and utilize our tools to send campaigns to your most engaged contacts first. Just knowing your open and click rate doesn’t accomplish anything unless you are reacting to it.

What can you do to improve your sending to Microsoft addresses?

As always, and to any provider or domain, send to contacts that have explicitly requested to receive emails from you. Send high quality, relevant content that your contacts would be compelled to open. Listen to your contacts - if they haven’t opened your recent emails, stop sending to them - remove them from your lists. Send in regular patterns and if you are sending on new IPs, ramp up your sending slowly.

If you are a new sender or are using a  new domain for sending, then it is a good idea to warm up the IP and domain prior to sending your main campaigns. Start with a very low volume of your most engaged addresses (even your own) and send them. If the email enters the spam folder, mark it as Not Spam. This will build your reputation with recipient servers. Each day add more volume - this will help with your delivery in long run.

Pay attention to your reputation and avoid spam traps.

Check out Elastic Email’s Contact Delivery and Optimization Tools. See how settings like Contact Pruning or Contact Delivery can help automate sending to your most engaged contacts over time. These settings can definitely help mitigate the impacts of this Microsoft change.

For more tips to help improve your delivery, please see our Delivery Guide. Find out more about how to keep your mail out of the spam folder, or check out our tips about reputation and delivery.

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Customer Success team member on the North American time zone. If you need help on this time zone, chances are I am available. Outside of work, you will most likely find me in the kitchen trying a new recipe or enjoying life on the lake.

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