Why is my email sender score low and what can I do about it?

Summary

A low sender score can stem from various factors, including sending volume, bounce rates, complaint rates, spam trap hits, authentication issues (SPF, DKIM, DMARC), content filtering by cable mailbox providers, and infrastructure problems. IP reputation affects deliverability, especially to Gmail users. Being listed on blocklists like Spamhaus SBL also hurts deliverability. Key actions include monitoring these metrics, maintaining a clean email list by removing unengaged subscribers, implementing email authentication, utilizing feedback loops to manage complaints, and gradually increasing sending volume. Some experts suggest focusing on actual delivery statistics instead of solely relying on sender score, while others note that the metric can fluctuate due to temporary issues. High bounce rates to specific domains may indicate blocks that require investigation.

Key findings

  • Multiple Factors Impact Score: Numerous factors affect sender score, including sending volume, bounce rates, complaint rates, spam traps, authentication, and infrastructure.
  • Engagement Matters: High engagement improves sender score, while low engagement or spam complaints worsen it.
  • Authentication is Crucial: Email authentication (SPF, DKIM, DMARC) is essential for identity verification and preventing spoofing.
  • List Hygiene is Key: Regularly cleaning your email list improves engagement and reduces bounces.
  • Volume Impacts Reputation: Sudden increases in sending volume can negatively affect sender score, particularly without proper IP warming.
  • IP Reputation Matters (Gmail): Google Postmaster Tools indicates that IP reputation significantly impacts deliverability to Gmail users.
  • Cable Providers Impact: Content filtering by cable mailbox providers may lower SenderScores.
  • SenderScore May Be Misleading: Some experts view sender score as unreliable and advise focusing on actual delivery statistics.

Key considerations

  • Monitor Key Metrics: Continuously monitor sending volume, bounce rates, complaint rates, spam traps, and authentication.
  • Maintain a Clean List: Regularly remove inactive or invalid addresses to improve engagement and lower bounce rates.
  • Authenticate Your Email: Implement SPF, DKIM, and DMARC to verify your sending identity.
  • Send Engaging Content: Create relevant content to improve engagement.
  • Utilize Feedback Loops: Implement FBLs to manage complaints and remove spammers.
  • Warm Up IPs: Gradually increase sending volume when using new IPs.
  • Consistent Sending Habits: Send emails on a regular schedule.
  • Review Google's Guidelines: Adhere to Google’s best practices for bulk email sending.
  • Avoid Blocklist Listing: Adhere to best practices to avoid being added to blocklists.
  • Address Domain-Specific Issues: Investigate and correct issues if specific domains are heavily bouncing.

What email marketers say
12Marketer opinions

A low sender score can be caused by various factors including sending volume, bounce rates, complaint rates, spam trap hits, authentication issues (SPF, DKIM, DMARC), content filtering and infrastructure problems. Sender score is also prone to fluctuations. To improve sender score, monitor these metrics, maintain a clean email list, authenticate your email, send valuable content, manage complaints, and follow consistent sending habits.

Key opinions

  • Multiple Factors Impact Score: Sender score is affected by a multitude of factors including sending volume, bounce rates, complaint rates, spam trap hits, and authentication practices.
  • Engagement is Crucial: High engagement rates positively impact sender score, while low engagement or spam complaints negatively affect it.
  • Authentication is Key: Proper email authentication (SPF, DKIM, DMARC) is essential for verifying your identity and preventing spoofing.
  • List Hygiene Matters: Regularly cleaning your email list by removing inactive or invalid email addresses can improve sender score.
  • Volume Impacts Score: Sudden increases in sending volume can negatively impact sender score, especially without proper IP warming.
  • Cable Providers Can Impact: Content filtering used by cable mailbox providers can cause rejections and lower sender scores.
  • SenderScore Bugs: SenderScore can show problems that don't exist. A bug can show messages filtered and rejected rates are flipped.

Key considerations

  • Monitor Key Metrics: Continuously monitor sending volume, bounce rates, complaint rates, spam trap hits, and authentication practices to identify areas for improvement.
  • Maintain a Clean List: Regularly remove inactive or invalid email addresses from your list to improve engagement and reduce bounce rates.
  • Authenticate Your Email: Implement SPF, DKIM, and DMARC to verify your sending identity and prevent spoofing.
  • Send Valuable Content: Focus on creating engaging and relevant content that subscribers want to receive to improve engagement rates.
  • Manage Complaints: Actively manage complaints by removing subscribers who mark your emails as spam from your list.
  • Warm-Up IPs: Gradually increase sending volume when using new IP addresses to establish a positive sending reputation.
  • Consistent Sending: Maintain consistent sending habits and predictable sending volumes to improve sender reputation. Also remove unengaged users as soon as possible.
  • Don't Panic over Fluctuations: Minor sender score fluctuations are normal and may not indicate a serious problem. Focus on maintaining consistent best practices.
Marketer view

Email marketer from EmailGeeks forum EmailPro responds that a sudden increase in sending volume can negatively impact sender score, especially if you're not gradually warming up your IP address. They advise gradually increasing volume over time.

May 2022 - EmailGeeks Forum
Marketer view

Email marketer from Mailchimp explains that factors influencing your sender score include sending volume, bounce rates, complaint rates, spam trap hits, and authentication practices. They advise monitoring these metrics to identify areas for improvement.

June 2023 - Mailchimp

What the experts say
7Expert opinions

A low sender score may not always be indicative of a real deliverability problem, and some experts suggest focusing on actual delivery statistics instead. However, sender reputation can be impacted by factors such as complaint rates, spam trap hits, authentication issues, and infrastructure problems. Addressing high bounce rates to specific domains (like optonline.net) and implementing feedback loops to manage complaints are important. List hygiene, ensuring you only email engaged subscribers and removing those who aren't, is also crucial.

Key opinions

  • Sender Score Reliability: Some experts consider sender score an unreliable metric and recommend focusing on actual delivery statistics.
  • Domain-Specific Blocks: High bounce rates to specific domains can indicate blocks and require investigation.
  • Reputation Impact Factors: Sender reputation is impacted by complaint rates, spam trap hits, authentication issues, and infrastructure problems.
  • Feedback Loops are Crucial: Utilizing feedback loops is crucial for managing complaints and improving sender reputation.
  • List Hygiene Importance: Maintaining email list hygiene is extremely important for deliverability.

Key considerations

  • Evaluate Score Utility: Assess whether sender score is providing valuable insights or if focusing on actual delivery metrics is more beneficial.
  • Investigate Domain Blocks: If high bounce rates to specific domains are observed, investigate the causes and take corrective actions.
  • Monitor Reputation Factors: Regularly monitor complaint rates, spam trap hits, authentication issues, and infrastructure problems to identify potential issues.
  • Implement Feedback Loops: Implement feedback loops to identify and remove subscribers who are marking your emails as spam.
  • Maintain List Hygiene: Ensure that people are removed from the list as soon as they are no longer engaging with your emails.
Expert view

Expert from Email Geeks points out high bounce rates to optonline.net and indicates a block. To investigate further, she suggests getting the bounce logs directly from Marketo to understand the rejection reasons.

April 2024 - Email Geeks
Expert view

Expert from Spamresource explains that sender reputation can be impacted by several metrics including complaint rates, spam trap hits, authentication issues and infrastructure problems. They suggest monitoring these metrics to find the cause of a low sender score and implementing changes.

June 2024 - Spamresource

What the documentation says
3Technical articles

A low sender score, and therefore email deliverability, is heavily influenced by IP reputation as Google Postmaster Tools indicates, and this poor reputation can cause emails to be marked as spam, which can be improved by following the guidelines and best practices for bulk email senders. Microsoft details this sender reputation is based on factors like complaint rates, spam trap hits, and sending infrastructure and recommends using their Smart Network Data Services (SNDS) to monitor IP reputation and troubleshoot deliverability issues. Spamhaus shares that being listed on their blocklists (like the SBL) negatively affects sender score and deliverability and adhere to best practices, obtain explicit consent from subscribers, and promptly process unsubscribe requests to avoid being listed.

Key findings

  • IP Reputation Matters: IP reputation significantly impacts email deliverability, particularly to Gmail users.
  • Factors Influencing Reputation: Sender reputation is based on factors such as complaint rates, spam trap hits, and sending infrastructure.
  • Blocklists Harm Deliverability: Being listed on blocklists like Spamhaus SBL negatively affects sender score and deliverability.

Key considerations

  • Review Google's Guidelines: Review and adhere to Google's guidelines and best practices for bulk email senders to improve reputation.
  • Monitor with SNDS: Use Microsoft's Smart Network Data Services (SNDS) to monitor IP reputation and troubleshoot deliverability issues.
  • Avoid Blocklist Listing: Adhere to best practices, obtain explicit consent from subscribers, and promptly process unsubscribe requests to avoid Spamhaus listing.
Technical article

Documentation from Spamhaus answers that being listed on their blocklists (like the SBL) negatively affects sender score and deliverability. They share that to avoid listing, adhere to best practices, obtain explicit consent from subscribers, and promptly process unsubscribe requests.

June 2021 - Spamhaus
Technical article

Documentation from Google Postmaster Tools shares that IP reputation affects deliverability to Gmail users. A low reputation can lead to emails being marked as spam. Google advises reviewing their guidelines and best practices for bulk email senders to improve reputation.

August 2021 - Google Postmaster Tools

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