Office 365/Hotmail Email Deliverability – July 2023

Office 365/Hotmail Email Deliverability – July 2023


Our deliverability team noticed a change with Office 365 emails, mostly .edu email domains that started in June and continued on to July. We also identified more strict spam controls for Hotmail[.]com, and Outlook[.]com personal email domains.

Office 365 - Email Scanning

Office365 has a few email security products. One is to track phishing and malware by scanning the links in an email. Most of the time this default is to scan on click which preserves the intent of that event for Email Service Providers (ESPs). In June there was a sharp increase in emails sent to .edu domains that on delivery scanned each link in the email using an IP address owned by Microsoft. All links are scanned at the time of delivery. While this is common for other email tools like Proofpoint, and Baracudda, this is new behavior for Office 365 domains. Word to the Wise has their own article tracking this back to the end of May Is .edu a canary?.

Bot Clicks in Campaign Deputy

Bot clicks have been an issue for less than <1% of delivered emails for Campaign Deputy customers. With this change in Office 365 we are going to make the following changes:

  • Create a new event “Bot Clicks”
  • Bot Clicks will now count towards the “Bot Clicks” category.
  • Add this new category to our Email Analytics similar to Apple’s MPP opens.
  • Update past bot clicks to this new category to allow for proper segmentation in emails.

While this is not an exhaustive list of all the changes, this will be the most visible change we will be making that our customers will see from their end.

We hope to complete creating the new event and back-dating the old bot clicks in the coming weeks. We will then focus on showing this information in our analytic reports later on.

Outlook, Hotmail, and Live domains

As part of our research in the bot clicks we also identified that a new filtering is being applied more aggressively to outlook[.]com, hotmail[.]com and live[.]com email addresses. These are hosted outside Office 365 though we suspect use similar rules minus the bot clicks. As part of this new change future segments to these domains should focus on the most actively engaged email addresses. Gmail can allow for 90 day active for some emails without any long-term deliverability impacts. Microsoft is more aggressive where we have seen email deliverability be blocked at 10% open rates. We recommend to segment your Microsoft emails to a closer group of engaged emails with limited re-engagement schedules to prevent any sort of block on your sending domain. 

As always we recommend to keep your main email list to the most active subscribers while dropping inactive emails every 30 days. A healthy open rate is above 20% across email providers which shows you have good deliverability.

*We use [.] when referring to a domain name as it’s industry best practice to prevent that domain from being linked to the real domain.

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