Summary
A decline in email open rates following increased sending volume on a shared IP is a complex issue stemming from several factors. The primary cause is a decrease in sender reputation due to ISPs viewing the sudden volume increase as suspicious, particularly if the IP wasn't properly warmed up. Other significant factors include poor list hygiene, leading to high bounce rates; low recipient engagement; deliverability problems stemming from shared IP reputation issues; and incorrect email authentication. Analyzing bounce reasons, monitoring IP blacklists and performance, A/B testing content, and using deliverability testing tools are crucial for troubleshooting and improving open rates. Ultimately, maintaining a good sender reputation, ensuring list hygiene, fostering engagement, and monitoring deliverability metrics are key to preventing this issue.
Key findings
- Sender Reputation: Increased volume on a shared IP can harm sender reputation, triggering spam filters.
- List Hygiene: Poor list hygiene (high bounce rates) damages reputation and lowers open rates.
- Engagement: Low recipient engagement (opens, clicks) leads to deliverability problems.
- Shared IP Issues: Reputation issues on a shared IP affect all users.
- Authentication: Incorrect SPF/DKIM/DMARC authentication causes deliverability problems.
- Warming Up: Lack of proper IP warming before increasing volume hurts deliverability.
Key considerations
- Check Blacklists: Verify if the shared IP is blacklisted.
- Monitor SNDS: Use Microsoft SNDS to monitor IP performance and identify problems.
- Analyze Bounce Reasons: Investigate bounce reasons to identify underlying issues.
- A/B Test Content: Experiment with different content to improve engagement.
- Test Deliverability: Use deliverability testing tools to identify and fix issues.
- Monitor Inbox Placement: Ensure emails are landing in the inbox, not the spam folder.
- Gradual Volume Increase: Increase sending volume gradually to avoid triggering spam filters.
What email marketers say
14 marketer opinions
A drop in email open rates after increasing sending volume on a shared IP can be attributed to several factors. Primarily, it signals potential issues with sender reputation due to the increased volume being perceived as suspicious activity by ISPs. Other factors include poor list hygiene leading to higher bounce rates, low recipient engagement, and deliverability problems stemming from shared IP reputation affected by other users. Proper email authentication, IP warm-up procedures, and inbox placement monitoring are also crucial. Ultimately, a complex interplay of factors, including data monitoring and troubleshooting, affects deliverability.
Key opinions
- Sender Reputation: Increased email volume on a shared IP can negatively impact sender reputation, causing ISPs to flag emails as spam.
- List Hygiene: Poor list hygiene, resulting in high bounce rates, damages sender reputation and lowers open rates.
- Engagement: Low recipient engagement leads to deliverability problems, as ISPs prioritize user interaction.
- Shared IP Reputation: Reputation issues on a shared IP affect all users, potentially impacting deliverability.
- Warming Up: Failing to properly warm up an IP address when increasing sending volume can hurt deliverability.
Key considerations
- IP Blacklisting: Check if the shared IP has been blacklisted, impacting email deliverability.
- Data Monitoring: Lack of detailed data, such as bounce codes and domain-specific open rates, hinders effective troubleshooting.
- Email Authentication: Ensure SPF, DKIM, and DMARC records are properly configured to prevent emails from being flagged as spam.
- Inbox Placement: Monitor inbox placement to identify if emails are landing in the spam folder instead of the inbox.
- Deliverability Testing: Implement deliverability testing to identify and fix issues affecting open rates.
Marketer view
Email marketer from GlockApps Blog shares that deliverability testing can help you identify and fix issues that are affecting your open rates. Use deliverability testing tools to check your spam score, inbox placement, and authentication settings. This can help you pinpoint the cause of your deliverability problems.
18 Aug 2023 - GlockApps Blog
Marketer view
Email marketer from Email on Acid Blog responds that poor list hygiene contributes to deliverability issues. If you're sending to a large number of inactive or invalid email addresses, it can increase your bounce rate and damage your sender reputation, leading to lower open rates. Regularly cleaning your email list is essential.
22 Feb 2022 - Email on Acid Blog
What the experts say
3 expert opinions
The drop in email open rates after increasing sending volume on a shared IP may stem from a few interconnected issues. Firstly, a sudden volume increase disrupts established sending patterns, triggering spam filters and hurting sender reputation. Secondly, the quality of the acquired list and the engagement of recipients play a vital role, with lower engagement causing deliverability problems. Lastly, examining bounce reasons can give indications of the cause of the lower open rates.
Key opinions
- Volume and Spam Filters: A sudden increase in email volume on a shared IP can trigger spam filters.
- List Quality: Poor list acquisition or low engagement can lead to decreased open rates.
- Bounce Reasons: Bounce reasons can provide insights into deliverability problems.
Key considerations
- Establish Sending Patterns: Maintain consistency and gradually increase sending volume to avoid triggering spam filters.
- Recipient Engagement: Focus on acquiring engaged recipients and maintaining high engagement levels.
- Analyze Bounce Reasons: Investigate bounce reasons to identify underlying deliverability issues.
Expert view
Expert from Spam Resource explains that a sudden increase in email volume, especially from a shared IP, can trigger spam filters because it deviates from established sending patterns. This can negatively affect your sender reputation, leading to lower open rates. Consistency and gradual increases are key.
28 Jan 2025 - Spam Resource
Expert view
Expert from Word to the Wise, Laura Atkins, responds that declining open rates after increasing sending volume from a shared IP may indicate issues with list acquisition or engagement. If the increased volume includes less engaged recipients, deliverability will suffer, as mailbox providers prioritize user engagement when filtering mail.
31 Dec 2021 - Word to the Wise
What the documentation says
3 technical articles
Email open rates dropping after increased volume on a shared IP are likely connected to sender reputation, authentication, and monitoring. Google Postmaster Tools emphasizes maintaining a good sender reputation and adjusting sending practices based on engagement. RFC documentation highlights the importance of correctly configured SPF records. Microsoft SNDS recommends monitoring IP health using their data services to identify issues.
Key findings
- Sender Reputation (Google): Maintaining a good sender reputation is vital; volume changes affect reputation, especially with low engagement.
- SPF Records (RFC): Improperly configured SPF records negatively impact deliverability on shared IPs.
- IP Health Monitoring (Microsoft SNDS): Using Microsoft SNDS allows monitoring of IP health, including complaint rates and spam trap hits.
Key considerations
- Monitor Sender Reputation: Actively monitor sender reputation using tools like Google Postmaster Tools.
- Configure SPF Records: Ensure SPF records accurately reflect sending sources for your domain.
- Utilize Microsoft SNDS: Use Microsoft SNDS to monitor IP health and identify potential issues affecting deliverability.
Technical article
Documentation from Google Postmaster Tools explains that maintaining a good sender reputation is vital for email deliverability. Significant changes in sending volume can affect your reputation, particularly if recipients aren't engaging with your emails. Google recommends monitoring your reputation and adjusting your sending practices accordingly.
22 Aug 2021 - Google Postmaster Tools
Technical article
Documentation from RFC explains that an improperly configured SPF record can negatively impact email deliverability, especially when using a shared IP. If your SPF record doesn't accurately reflect the sending sources for your domain, ISPs may flag your emails as suspicious, leading to lower open rates.
17 Mar 2024 - RFC
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