Emails going to spam in Outlook.com is a multifaceted issue. It's influenced by factors like sender reputation (based on engagement, complaint rates, and list hygiene), email authentication (SPF, DKIM, DMARC), sending limits, and content. Outlook.com can be particularly challenging even for senders with good reputations. Practices like list bombing, mismatched 'From' addresses, and sending to spam traps worsen deliverability. While Outlook.com isn't always down, technical misconfigurations and failure to adhere to email best practices contribute significantly. User interaction (marking as 'not junk') can improve inbox placement, and testing tools can help diagnose issues.
9 marketer opinions
Emails often land in Outlook.com's spam folder due to a combination of factors. These include a poor sender reputation stemming from low engagement, sending to spam traps, or poor list hygiene; authentication issues related to SPF, DKIM, and DMARC misconfiguration; content that triggers spam filters; and mismatches between the 'From' address and the sending server. Additionally, Outlook.com can be particularly challenging, sometimes even flagging legitimate email as spam due to its unique filtering algorithms. User interaction, such as marking emails as 'not junk,' can positively influence future deliverability. Using email testing tools can identify these issues, and following email best practices is critical.
Marketer view
Email marketer from StackExchange says that content can affect if you go to spam; he says that the usage of specific words, especially 'spammy' ones, can trigger spam filters and cause deliverability issues to Outlook.com and other providers.
14 Aug 2021 - StackExchange
Marketer view
Email marketer from Mailtrap explains that sending emails to spam traps can damage your sender reputation and lead to emails being filtered as spam in Outlook.com. Proper list hygiene is essential.
18 Nov 2021 - Mailtrap.io
5 expert opinions
Emails may land in Outlook.com's spam folder for various reasons. While Outlook.com isn't always down, deliverability issues can arise even with a high sender score. A poor sender reputation, stemming from negative sending history, high complaint rates, and not adhering to email best practices, is a major contributing factor. Implementing and enforcing DMARC can improve deliverability by preventing domain spoofing. List bombing, which is signing someone up for subscriptions without consent, negatively impacts deliverability to Outlook.com.
Expert view
Expert from Word to the Wise shares that list bombing will impact email deliverability to providers like Outlook.com. List bombing refers to the practice of signing someone up for numerous newsletters and other subscriptions without their consent.
16 Jan 2025 - Word to the Wise
Expert view
Expert from Spam Resource explains that a poor sender reputation is a major factor causing emails to land in Outlook.com's spam folder. This reputation is based on sending history, complaint rates, and adherence to email best practices.
20 Apr 2025 - Spam Resource
4 technical articles
Emails land in Outlook.com spam folders due to several technical and policy-related issues. Exceeding sending limits set by Outlook.com to prevent spam can result in emails being flagged or blocked. Incorrect or missing DMARC records lead to authentication failures and spam placement. Similarly, an improperly configured or absent SPF record compromises email authentication and can cause spam filtering. Following general email sending best practices, such as easy unsubscribe options, also improves deliverability across various providers, including Outlook.com.
Technical article
Documentation from RFC-Editor.org details that an improperly configured SPF record, or lack thereof, can lead to emails being flagged as spam by Outlook.com. Validating the SPF record is important to ensure proper email authentication.
16 Oct 2022 - RFC-Editor.org
Technical article
Documentation from DMARC.org explains that incorrect or missing DMARC records can cause emails to fail authentication checks, leading to spam placement in Outlook.com. Proper configuration is crucial for deliverability.
22 Apr 2022 - DMARC.org
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