Summary
Rate limiting of transactional emails from WordPress sites using Mailgun by Outlook and Yahoo arises from a combination of factors. Shared IP reputation, influenced by other users' sending habits and spam complaints, is a major contributor. Microsoft and Yahoo prioritize IP and domain reputation, authentication (SPF, DKIM, DMARC), and user engagement when filtering emails. Misconfigured WordPress plugins, incorrect DNS records, and low email volume can also trigger rate limits. Experts recommend ensuring proper authentication, monitoring sender reputation, gradually warming up new IPs, practicing list hygiene, and considering dedicated IPs for better control. Additionally, if migrating from a VPS like OVH, it's important to allow time for the IP's reputation to improve.
Key findings
- Shared IP Reputation: Mailgun's shared IPs are vulnerable to the sending practices of other users, affecting overall IP reputation and deliverability.
- Authentication Importance: Proper configuration and alignment of SPF, DKIM, and DMARC records are crucial for email authentication and avoiding spam filters.
- Domain and Sending History: The history of the sending domain, including previous deliverability issues and spam complaints, significantly impacts deliverability.
- Microsoft & Yahoo Prioritization: Outlook.com and Yahoo Mail prioritize IP and domain reputation, authentication, and user engagement in email filtering.
- Volume Impact: Very low sending volume can hinder building a positive IP reputation, raising suspicion from email providers.
Key considerations
- Monitor Sending Reputation: Continuously monitor IP and domain reputation to identify and address any issues promptly.
- Verify Authentication Setup: Thoroughly verify and maintain the correct configuration of SPF, DKIM, and DMARC records.
- Dedicated IP Consideration: Assess whether a dedicated IP is necessary for greater control over sending reputation and deliverability.
- Gradual IP Warm-up: Gradually increase sending volume when using new IPs to build a positive reputation with email providers.
- Practice List Hygiene: Regularly clean email lists by removing unengaged users and invalid addresses to minimize bounce rates and spam complaints.
- Plugin and WordPress Configuration: Ensure all WordPress plugins are up-to-date, properly configured and don't affect sending configuration
- Account for Delayed Delivery: Understand that the 4.7.650 error may result in delayed email delivery.
What email marketers say
9 marketer opinions
Transactional emails from WordPress sites using Mailgun may face rate limiting by Outlook and Yahoo due to various factors. The primary cause is often related to IP reputation issues, especially when using shared IPs. Poor sending practices by other users on the same IP can negatively impact deliverability. Additionally, misconfigured WordPress plugins, incorrect DNS records (SPF, DKIM, DMARC), and low email volume can contribute to rate limiting. Gradual IP warm-up, monitoring sender reputation, and ensuring proper authentication settings are crucial for improving deliverability.
Key opinions
- IP Reputation: Shared IPs on Mailgun are susceptible to negative reputation impacts from other users' sending habits.
- Plugin Configuration: Misconfigured or outdated WordPress plugins can lead to incorrect headers and spam filter triggers.
- DNS Records: Incorrect or missing SPF, DKIM, and DMARC records can cause email providers to distrust emails.
- Email Volume: Very low email volume can make it difficult to build a positive IP reputation, leading to suspicion.
Key considerations
- Shared vs. Dedicated IP: Evaluate whether a shared IP is sufficient, or if a dedicated IP is needed for better control over reputation.
- DNS Configuration: Ensure SPF, DKIM, and DMARC records are correctly configured and validated.
- IP Warm-up: If using a new IP, gradually warm it up by increasing email volume over time.
- Plugin Review: Regularly review and update WordPress plugins to avoid misconfigurations.
- Sender Reputation Monitoring: Continuously monitor sender reputation and adjust practices to maintain good standing.
- Authentication Settings: Ensure your WordPress website has correct authentication settings to prevent being marked as spam.
Marketer view
Email marketer from Reddit shares that shared IP addresses on Mailgun can be affected by other users' sending habits. If another user on the same IP is sending spam or has poor sending practices, it can negatively impact the IP's reputation, leading to rate limiting by providers like Outlook and Yahoo.
22 Jul 2024 - Reddit
Marketer view
Email marketer from Stack Overflow explains that WordPress plugins might be misconfigured or outdated, leading to incorrect headers or sending practices that trigger spam filters. Checks SPF and DKIM records are essential.
14 May 2023 - Stack Overflow
What the experts say
8 expert opinions
Transactional emails from WordPress sites using Mailgun can be rate-limited by Outlook and Yahoo due to several factors. While the IP may be shared with decent reputation, ensuring authentication aligns with the sending domain is crucial. Domain reputation is tricky to measure, so understanding the sending history, implementing captchas/limits, and knowing previous deliverability issues are important. A new mailstream may simply need time for filters to adjust. Sending directly from WordPress on a poor reputation VPS like OVH can negatively impact deliverability, so Mailgun is a better solution, but requires time to settle. Shared IPs also pose a risk if other users engage in poor practices. Correct authentication (SPF, DKIM, DMARC) is vital, even for transactional emails.
Key opinions
- IP Reputation: Shared IPs can be affected by the sending practices of other users.
- Authentication Alignment: Ensuring authentication aligns with the from domain is critical.
- Domain Reputation: Understanding the domain's sending history is key to diagnosing issues.
- OVH Reputation: Sending directly from WordPress on an OVH VPS results in poor deliverability.
- 4xx Deferrals: A 4.7.650 error indicates a deferral; emails will either be delivered later or rejected.
Key considerations
- Give it Time: If it's a new mailstream, allow time for filters to adjust.
- Review Authentication: Ensure proper authentication (SPF, DKIM, DMARC) is configured.
- Assess Domain History: Investigate the domain's sending history, including previous deliverability issues.
- WordPress Security: Be aware of potential WordPress security vulnerabilities and subscription bomb attacks.
- Shared IP Risks: Understand the risks associated with shared IPs and the sending practices of other users.
- Avoid Private IPs (Potentially): Private IPs are not recommended for such low volume sending.
Expert view
Expert from Spam Resource, Laura Atkins, explains that using shared IPs can lead to deliverability issues if other users on the same IP engage in poor sending practices. This affects the overall IP reputation and can cause rate limiting by email providers.
2 Sep 2022 - Spam Resource
Expert view
Expert from Email Geeks explains that the 4.7.650 error code indicates a 4xx deferral, meaning the email will eventually be delivered or rejected. If rejections are not seen, the issue is delayed email sending.
28 Nov 2023 - Email Geeks
What the documentation says
4 technical articles
Microsoft, Yahoo, Mailgun, and Postmark documentation highlight key factors contributing to rate limiting of transactional emails from WordPress sites using Mailgun. Outlook.com filters email based on IP reputation, influenced by spam complaints, bounce rates, and spam traps. Yahoo Mail considers sender authentication, reputation, and user engagement. Mailgun emphasizes the impact of shared IPs, where other users' poor practices affect deliverability. Postmark advises proper authentication, monitoring bounce rates, segmentation, and separating transactional and marketing emails.
Key findings
- IP Reputation (Microsoft): Outlook.com uses IP reputation as a key factor in filtering email; low reputation leads to rate limiting.
- Sender Authentication (Yahoo): Yahoo Mail considers sender authentication (SPF, DKIM, DMARC), sender reputation, and user engagement.
- Shared IP Impact (Mailgun): Using a shared IP means your reputation is influenced by other Mailgun customers; poor practices affect you.
- Deliverability Improvements (Postmark): Proper authentication, monitoring bounce rates, segmentation, and separating email types improve deliverability.
Key considerations
- Monitor IP Reputation: Regularly monitor IP reputation and address issues like spam complaints and high bounce rates.
- Implement Strong Authentication: Ensure SPF, DKIM, and DMARC are correctly configured to authenticate your emails.
- Consider Dedicated IP: If shared IP issues persist, consider using a dedicated IP for more control over your reputation.
- Practice List Hygiene: Segment your email list and remove unengaged users to reduce bounce rates and improve engagement.
- Separate Email Types: Send transactional emails from a different IP address or domain than marketing emails.
Technical article
Documentation from Mailgun explains that using a shared IP means your email sending reputation is influenced by other Mailgun customers using the same IP. If their sending practices are poor, it can negatively affect your deliverability. Dedicated IPs offer more control over your reputation.
2 Sep 2022 - Mailgun
Technical article
Documentation from Postmark shares that to improve deliverability with transactional emails, ensure proper authentication (SPF, DKIM, DMARC), monitor bounce rates, and segment your email list to only send to engaged users. Also, avoid sending marketing emails from the same IP address as transactional emails.
7 Aug 2024 - Postmark
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