Summary
WordPress emails are often blocked by Outlook, especially when sent from the same domain, due to a combination of factors related to authentication, sender reputation, server configuration, and email content. Key issues include missing or misconfigured SPF and DKIM records, poor IP reputation of the hosting server, sending from the same domain as the recipient's Outlook address (potentially causing a loop or conflict), strict spam filtering by Outlook, and interference from security plugins. Additionally, using a free email address as the 'From' address and failing to maintain good list hygiene contribute to deliverability problems. It is recommended to use an SMTP plugin with a reputable external email service, correctly configure DNS records, monitor sender reputation, review email content, and check email logs for error messages.
Key findings
- Authentication: Missing or misconfigured SPF and DKIM records are a primary reason for Outlook blocking WordPress emails.
- IP Reputation: Poor IP reputation of the web hosting server leads to emails being flagged as spam.
- Domain Conflict: Sending from the same domain as the recipient's Outlook address can cause internal conflicts and filtering issues.
- Spam Filtering: Outlook employs strict spam filtering technologies that can be triggered by specific content or phrases.
- List Hygiene: Sending emails to old and unengaged addresses damages sender reputation and increases the likelihood of being blocked.
- O365 Security Settings: Security settings within O365, particularly in GoDaddy-purchased instances, can cause deliverability problems.
Key considerations
- SMTP Plugin: Implement an SMTP plugin to use an external email sending service (e.g., SendGrid, Mailgun, Brevo) for reliable delivery.
- DNS Records: Ensure that DNS records (MX, SPF, DKIM, rDNS) are correctly configured.
- Sender Reputation: Monitor and maintain a good sender and domain reputation.
- Email Content: Review and optimize email content to avoid triggering spam filters.
- Email Logging: Check email logs for errors and clues about deliverability issues.
- GoDaddy O365: If using a GoDaddy-purchased O365 instance, review specific security settings.
- Message Trace: Run a message trace in M365 if the Outlook recipient is an M365 mailbox.
What email marketers say
11 marketer opinions
WordPress emails often face deliverability issues with Outlook, particularly when sent from the same domain. This is often due to a combination of factors including improper email authentication (SPF, DKIM), poor IP reputation of the web host, conflicts arising from using the same domain for both sending and receiving, strict spam filtering by Outlook, and interference from security plugins. Utilizing SMTP plugins with reputable external email services is a common recommendation to bypass these problems. It's also essential to review DNS records, sender reputation, email content, and WordPress configurations to ensure proper setup and avoid triggering spam filters.
Key opinions
- Authentication: WordPress emails often lack proper authentication (SPF, DKIM), causing Outlook to flag them as spam. Implement proper authentication methods using an SMTP plugin.
- IP Reputation: Poor IP reputation of the web hosting server can lead to emails being blocked. Use a reputable email service provider (ESP) or a transactional email service with a dedicated IP.
- Domain Conflict: Sending emails from the same domain as the recipient's Outlook email can cause internal conflicts. Use a separate subdomain for sending emails.
- Strict Filtering: Outlook has strict spam filtering rules, which can be triggered by certain keywords or phrases in the email content. Review and adjust the email content to avoid triggering these filters.
- Plugin Interference: Security plugins can sometimes interfere with WordPress's ability to send emails. Temporarily disable or reconfigure these plugins to ensure they're not causing deliverability problems.
Key considerations
- SMTP Plugin: Use an SMTP plugin to connect to a dedicated email sending service (e.g., SendGrid, Mailgun, Brevo) for better deliverability.
- DNS Records: Ensure that DNS records (MX, SPF, DKIM) are correctly configured for the domain.
- Sender Reputation: Monitor and maintain a good sender reputation to avoid being blacklisted by email providers.
- Email Content: Review and optimize email content to avoid triggering spam filters. Avoid using spammy keywords or phrases.
- Logging: Check email logs for error messages or clues about deliverability issues. This can help diagnose the problem and identify potential solutions.
- Message Trace: Run a message trace in M365 if the Outlook recipient is an M365 mailbox
Marketer view
Email marketer from WP Mail SMTP shares that if the 'From' email address in your WordPress settings is a free email address (like Gmail or Yahoo), Outlook may be more likely to block the email. Using an email address associated with your domain can improve deliverability.
2 Jan 2024 - WP Mail SMTP
Marketer view
Email marketer from MailPoet recommends checking your email logs for any error messages or clues about why emails are being blocked. Many SMTP plugins provide logging features that can help you diagnose the problem. Also, test different email subjects and content to see if specific words or phrases are triggering spam filters.
22 Oct 2022 - MailPoet
What the experts say
6 expert opinions
Several experts indicate that WordPress emails blocked by Outlook, especially from the same domain, often result from authentication problems (SPF, DKIM), domain reputation issues, and security settings within O365. GoDaddy-purchased O365 instances have extra security measures that can cause issues. Maintaining good list hygiene by removing old and unengaged addresses is also critical to prevent spam complaints and protect sender reputation.
Key opinions
- Authentication Issues: Missing or misconfigured SPF and DKIM records are common causes for deliverability problems.
- Domain Reputation: A poor domain reputation due to past spam associations or bad sending practices can lead to emails being blocked by Outlook.
- Security Settings in O365: Security settings within O365, particularly in GoDaddy-purchased instances, can cause deliverability problems.
- List Hygiene: Sending to old or unengaged addresses increases the risk of spam complaints and damages sender reputation.
Key considerations
- Check Authentication Records: Ensure SPF and DKIM records are correctly configured to authenticate your emails.
- Monitor Domain Reputation: Regularly check your domain reputation and take steps to improve it if necessary.
- Review O365 Security Settings: If using O365, review and adjust security settings to ensure they are not blocking legitimate emails, especially in GoDaddy-purchased instances.
- Clean Email Lists: Implement a process for regularly cleaning email lists to remove unengaged or old addresses.
Expert view
Expert from Email Geeks explains the issue may stem from using a Godaddy-purchased O365 instance, which has extra security measures, and suggests contacting Godaddy for assistance with custom settings.
15 Sep 2022 - Email Geeks
Expert view
Expert from Spam Resource explains that your domain's reputation is critical for deliverability. If your domain has been associated with spam in the past or has poor sending practices, Outlook is more likely to block your emails.
30 Jun 2023 - Spam Resource
What the documentation says
4 technical articles
According to documentation from Microsoft, EasyWP, Postmark, and RFC Editor, WordPress emails are often blocked by Outlook due to a confluence of factors. These include Outlook's filtering technologies that consider sender IP reputation, domain reputation, email content, and authentication methods. SPF records are crucial for specifying authorized mail servers, and missing or misconfigured DKIM records can cause emails to be flagged as spam. Additionally, a valid Reverse DNS (rDNS) record helps verify the legitimacy of the mail server. Sending from the same domain as Outlook.com mailboxes without proper configuration can also create internal confusion and filtering issues.
Key findings
- Outlook Filtering: Outlook.com employs filtering technologies that evaluate sender IP reputation, domain reputation, content, and authentication.
- SPF Record Importance: SPF records are crucial for specifying authorized mail servers. Without a proper SPF record, Outlook may flag emails as suspicious.
- DKIM Signature: DKIM records add a digital signature to outgoing emails, verifying the sender's identity and ensuring the email hasn't been tampered with.
- Reverse DNS: A valid Reverse DNS (rDNS) record helps verify that the mail server is legitimate, improving email deliverability.
- Domain Configuration: Sending from a domain that also has Outlook.com mailboxes can create internal confusion and filtering issues if not properly configured.
Key considerations
- Review Authentication: Ensure SPF and DKIM records are correctly configured and up-to-date.
- Check IP and Domain Reputation: Monitor your sender IP and domain reputation to ensure they are not negatively impacting deliverability.
- Configure rDNS: Set up a valid Reverse DNS (rDNS) record for your mail server.
- Email Content: Review email content for spam triggers that may cause Outlook to filter the messages.
- Correct DNS records: Correct DNS records for the sending domain.
Technical article
Documentation from RFC Editor (Request for Comments) explains that having a valid Reverse DNS (rDNS) record for your mail server can help improve email deliverability. An rDNS record maps an IP address to a domain name, and it's used to verify that the mail server is legitimate.
28 Sep 2021 - RFC-Editor
Technical article
Documentation from EasyWP SMTP Plugin explains that a Sender Policy Framework (SPF) record is crucial. It specifies which mail servers are authorized to send emails on behalf of your domain. If the WordPress server isn't listed in the SPF record, Outlook may flag emails as suspicious, especially if the 'From' address uses the same domain as the recipient's Outlook address.
27 Dec 2021 - EasyWP
