Summary
Email deliverability problems with Outlook.com stem from a confluence of factors relating to sender reputation, list hygiene, authentication, content quality, and user engagement. Microsoft places significant emphasis on sender reputation, which is influenced by complaint rates, engagement metrics, and authentication protocols. Sending from new IPs, maintaining clean lists, avoiding spam triggers in content, gradual sending volume increases, and valid email authentication (SPF, DKIM, DMARC) all play crucial roles in ensuring emails reach the inbox.
Key findings
- Sender Reputation Matters: A poor sender reputation, encompassing IP, domain, and sending practices, is a primary cause of Outlook deliverability problems.
- Engagement is Key: Low user engagement (low open rates, click-through rates) negatively impacts deliverability as Microsoft actively tracks engagement metrics.
- Authentication is Mandatory: Lack of proper email authentication (SPF, DKIM, DMARC) prevents Outlook from verifying the legitimacy of emails, increasing the likelihood of emails being flagged as spam.
- List Quality Counts: Poor list hygiene, including sending to unengaged users or outdated addresses, directly increases bounce rates, complaints, and negatively impacts sender reputation.
- Content Impacts Deliverability: The content of your emails, including the use of spam trigger words, URL shorteners, and poor HTML coding, can trigger spam filters and hinder deliverability.
Key considerations
- Monitor & Maintain Sender Reputation: Actively monitor your sender reputation using tools like SNDS and take prompt action to address any issues such as blocklisting or high complaint rates.
- Prioritize User Engagement: Segment your email lists based on engagement levels and tailor content to resonate with each segment, encouraging opens, clicks, and conversions.
- Implement Full Email Authentication: Ensure complete and correct implementation of SPF, DKIM, and DMARC records to authenticate your sending domain and prove that your emails are legitimate.
- Practice Strict List Hygiene: Regularly clean your email lists by removing inactive subscribers and implementing a double opt-in process to ensure that only engaged and valid email addresses are added.
- Optimize Email Content: Craft compelling and relevant email content while avoiding spam trigger words, using reputable links, and ensuring responsive and well-coded HTML templates to enhance the user experience.
What email marketers say
16 marketer opinions
Several factors contribute to email deliverability issues with Outlook.com. Key factors include low engagement rates, sending from new IP addresses or domains, poor list hygiene, lack of proper email authentication (SPF, DKIM, DMARC), being listed on blocklists, sending unsolicited emails, using URL shorteners or spam trigger words, inconsistent sending volume, and poorly coded email templates. Microsoft weighs sender reputation and engagement heavily, making list quality and authentication critical.
Key opinions
- Engagement: Low engagement (low open rates, click-through rates) negatively impacts deliverability as Outlook weighs user engagement heavily.
- Sender Reputation: A damaged sender reputation (IP, domain, and sending practices) due to factors like blocklisting or spam complaints will lead to deliverability problems.
- Authentication: Lack of proper email authentication (SPF, DKIM, DMARC) prevents Outlook from verifying the legitimacy of your emails.
- List Hygiene: Poor list hygiene (sending to outdated, inactive, or purchased lists) results in high bounce rates and spam complaints.
- Content: Using URL shorteners or spam trigger words in email content can cause Outlook to flag emails as spam.
Key considerations
- Monitor Engagement: Track engagement metrics and segment lists to target active and interested subscribers.
- Authenticate Email: Implement SPF, DKIM, and DMARC to authenticate your sending domain.
- Maintain List Hygiene: Regularly clean your email lists to remove inactive or invalid addresses.
- Content Quality: Avoid using spam trigger words, URL shorteners, and poorly coded email templates.
- Gradual Volume Increase: When sending from new IP addresses or domains, gradually increase sending volume to build trust with Outlook.
Marketer view
Email marketer from Email Geeks explains it's probably lack of a custom/aligned return path (5321.From) domain with a legitimate source as opposed to something dodgy, and that DMARC is still passing as their DKIM seems to be aligned.
22 Jan 2024 - Email Geeks
Marketer view
Email marketer from Mailjet explains that poor list hygiene (sending to outdated, inactive, or purchased lists) can lead to high bounce rates and spam complaints, negatively impacting your sender reputation with Outlook.
15 Nov 2022 - Mailjet
What the experts say
3 expert opinions
Deliverability problems with Outlook.com are commonly caused by poor sender reputation, which is influenced by factors such as sending to unengaged users and high complaint rates. Microsoft heavily relies on sender reputation and engagement metrics to filter emails.
Key opinions
- Sender Reputation: Poor sender reputation (IP, domain, and sending practices) is a primary cause of deliverability issues with Outlook.com.
- User Engagement: Consistently sending to unengaged users significantly hurts deliverability due to Microsoft actively tracking engagement metrics.
- Complaint Rates: High complaint rates, where recipients mark emails as spam, negatively impact sender reputation and lead to filtering.
Key considerations
- Monitor Sender Reputation: Actively monitor your sender reputation and take steps to address any issues that may arise.
- Improve User Engagement: Focus on sending relevant content to engaged users and segment your lists accordingly.
- Reduce Complaint Rates: Implement measures to reduce complaint rates, such as improving email content and making it easy for recipients to unsubscribe.
Expert view
Expert from Word to the Wise responds by sharing that consistently sending to unengaged users significantly hurts deliverability. Microsoft actively tracks engagement metrics, so targeting inactive or uninterested subscribers leads to increased spam filtering.
4 Jan 2023 - Word to the Wise
Expert view
Expert from Spam Resource explains that poor sender reputation is a primary cause; Microsoft heavily relies on sender reputation, so a damaged reputation will lead to deliverability issues. This includes IP reputation, domain reputation, and the reputation of your sending practices.
24 Feb 2023 - Spam Resource
What the documentation says
3 technical articles
Microsoft documentation identifies several common causes of email deliverability problems with Outlook.com. These include failing to properly authenticate your sending domain using SPF, DKIM, and DMARC; being listed on blocklists; and sending unsolicited or unwanted emails. Ensuring proper authentication, monitoring blocklist status, and obtaining explicit consent from recipients are crucial for maintaining deliverability.
Key findings
- Authentication Failure: Lack of proper SPF, DKIM, and DMARC authentication prevents Outlook from verifying that you are authorized to send emails on behalf of your domain.
- Blocklisting: Being listed on blocklists (RBLs) is a common cause of deliverability issues.
- Unsolicited Email: Sending emails considered unsolicited or unwanted by recipients (due to lack of consent or difficulty unsubscribing) can lead to deliverability problems.
Key considerations
- Implement Authentication: Ensure your sending domain is properly authenticated with SPF, DKIM, and DMARC.
- Monitor Blocklists: Regularly check if your IP address or domain is on any major blocklists and take steps to get delisted if necessary.
- Obtain Explicit Consent: Ensure recipients explicitly consent to receive emails from you, and provide a clear and easy way to unsubscribe.
Technical article
Documentation from Microsoft explains that Sending emails that are considered unsolicited or unwanted by recipients can lead to deliverability issues. This can happen if recipients did not explicitly consent to receive emails from you, or if they have difficulty unsubscribing from your mailing list.
12 Dec 2021 - Microsoft
Technical article
Documentation from Microsoft explains that ensure your sending domain is properly authenticated with SPF, DKIM, and DMARC. This helps Outlook verify that you are authorized to send emails on behalf of your domain.
1 Jan 2023 - Microsoft
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