10 Ways to Reduce Email Delivery Failures


Email is the most vital of communication tools for both businesses and individuals alike. However, many people face the frustrating issue of email delivery failures, where emails bounce back or land in spam folders instead of reaching the intended recipient. In fact it’s our least liked support category at TVA.

Understanding and addressing the causes of these failures can significantly enhance your email deliverability. 

In this article, we will explore ten effective ways to reduce email delivery failures, introducing key concepts like DMARC, SPF, and DKIM. We’ll try to keep it simple and practical, so even non-technical readers can follow along.

Table of Contents

Authenticate Your Emails with SPF

What is SPF? 

Sender Policy Framework (SPF) is an email authentication method designed to prevent spammers from sending messages on behalf of your domain. It allows domain owners to specify which mail servers are permitted to send email on behalf of their domain.


Imagine you own the domain mybusiness.com. By setting up an SPF record, you tell email servers that only specific IP addresses (like your mail server’s IP) are authorized to send emails from mybusiness.com.

How to Set Up SPF:

  1. Identify the IP addresses that send emails for your domain.
  2. Create an SPF record in your domain’s DNS settings.
  3. Publish the SPF record with a list of allowed IP addresses.



  • Helps prevent spoofing and phishing.
  • Improves email deliverability.


  • Requires updating the SPF record if you change your mail server.
  • Limited to 10 DNS lookups, which can be restrictive for larger organizations.



Implement DKIM to Verify Email Integrity

What is DKIM? 

DomainKeys Identified Mail (DKIM) adds a digital signature to your emails, allowing the receiving mail server to verify that the email was indeed sent by the domain owner and has not been altered in transit.


When you send an email from [email protected], DKIM adds a signature to the header. The recipient’s server uses this signature to check if the email was truly sent by mybusiness.com.

How to Set Up DKIM:

  1. Generate a DKIM key pair (public and private).
  2. Publish the public key in your DNS settings as a TXT record.
  3. Configure your mail server to sign outgoing emails with the private key.


  • Verifies the authenticity of your emails.
  • Prevents tampering of email content.


  • Requires technical setup and maintenance.
  • Incorrect configuration can lead to delivery issues.


DKIM Signature Email Error
DKIM Signature Error

Use DMARC for Enhanced Email Security

What is DMARC? 

Domain-based Message Authentication, Reporting, and Conformance (DMARC) builds on SPF and DKIM by allowing domain owners to specify how emails that fail authentication should be handled.


DMARC lets you instruct email providers to quarantine or reject emails that fail SPF or DKIM checks for mybusiness.com.

How to Set Up DMARC:

  1. Create a DMARC policy specifying actions for failed emails.
  2. Publish the policy in your DNS as a TXT record.
  3. Monitor DMARC reports to adjust policies as needed.


  • Provides visibility into email authentication.
  • Reduces phishing and spoofing risks.


  • Requires proper SPF and DKIM setup.
  • Can initially block legitimate emails if not configured carefully.


Keep Your Email Lists Clean

What is a Clean Email List? 

A clean email list contains only valid and active email addresses. Regularly removing inactive or incorrect addresses helps reduce bounce rates and improves deliverability.


If you have 10,000 email subscribers but 2,000 addresses frequently bounce back, cleaning your list will remove these invalid addresses, reducing the risk of being marked as spam.

How to Clean Your Email List:

  1. Use email verification tools to check addresses.
  2. Remove hard bounces (permanently undeliverable emails).
  3. Regularly update your list by removing inactive subscribers.


  • Improves deliverability and engagement.
  • Reduces the risk of being blacklisted.


  • Requires ongoing maintenance.
  • May reduce the size of your email list.


Avoid Spammy Content

What is Spammy Content? 

Spammy content includes certain words, phrases, or formatting that can trigger spam filters. Examples include excessive use of exclamation marks, all caps, or phrases like “Buy now” and “Free offer”.


An email with the subject “ACT NOW!!! Get FREE!!! Access to Our Product” is likely to be flagged as spam.

How to Avoid Spammy Content:

  1. Use clear, concise language.
  2. Avoid excessive punctuation and capital letters.
  3. Test your emails using spam-checking tools.


  • Improves email deliverability.
  • Enhances readability and engagement.


  • Requires careful crafting of email content.
  • May limit the use of promotional language.


Monitor Your Sending Reputation

What is Sending Reputation? 

Your sending reputation is a score that ISPs (Internet Service Providers) assign to your domain based on your email-sending practices. A poor reputation can lead to emails being blocked or marked as spam.


If you frequently send emails to invalid addresses or have high spam complaint rates, your domain’s reputation may suffer, causing more emails to be filtered out.

How to Monitor Sending Reputation:

  1. Use tools like Google Postmaster Tools or Sender Score.
  2. Track metrics such as bounce rates, spam complaints, and open rates.
  3. Adjust your email practices based on feedback.


  • Provides insights into deliverability issues.
  • Helps maintain a good sender reputation.


  • Requires regular monitoring and adjustments.
  • May need technical tools for accurate tracking.


Segment Your Email List

What is Email Segmentation? 

Segmentation involves dividing your email list into smaller groups based on specific criteria like demographics, interests, or purchase history. This allows for more targeted and relevant email campaigns.


Instead of sending the same email to all 10,000 subscribers, you can segment your list into groups like “New Customers” and “Loyal Customers” to tailor your messaging.

How to Segment Your Email List:

  1. Collect data on your subscribers (e.g., through sign-up forms).
  2. Use email marketing tools to create segments based on criteria.
  3. Send customized emails to each segment.


  • Increases engagement and conversion rates.
  • Reduces unsubscribe rates.


  • Requires data collection and analysis.
  • Can be time-consuming to set up and manage.


Use a Reliable Email Service Provider (ESP)

What is an ESP? 

An Email Service Provider (ESP) is a platform that helps you send marketing emails, transactional emails, and other types of messages. Reliable ESPs offer features like high deliverability rates, analytics, and automation.


Using a reputable ESP like Mailchimp, Sendinblue, or Constant Contact can ensure your emails are delivered on time and with minimal risk of being marked as spam.

How to Choose an ESP:

  1. Compare features and pricing of different ESPs.
  2. Look for ESPs with good reputations and deliverability rates.
  3. Test the ESP’s support and user interface.


  • Simplifies email sending and management.
  • Provides tools for tracking and improving deliverability.


  • Can be expensive depending on the provider.
  • Limited customization compared to self-hosted solutions.


Configure Bounce Handling

What is Bounce Handling?

Bounce handling involves managing emails that cannot be delivered. Bounces are categorized as “hard” (permanent issues) or “soft” (temporary issues).


If you send an email to [email protected] and it bounces back because the mailbox is full (soft bounce), you might try sending it again later. For a hard bounce (e.g., invalid address), you should remove it from your list.

How to Configure Bounce Handling:

  1. Use your ESP’s bounce handling features or set up manual scripts.
  2. Regularly review bounce reports.
  3. Remove or correct hard bounce addresses.


  • Keeps your email list healthy.
  • Reduces the risk of being blacklisted.


  • Requires ongoing monitoring and updates.
  • Soft bounces need careful handling to avoid unnecessary removals.


Enable Feedback Loops

What is a Feedback Loop?

A Feedback Loop (FBL) is a system where ISPs notify you about spam complaints made by recipients. This helps you identify and address issues that lead to complaints.


If users mark your emails as spam, an FBL can alert you, allowing you to remove these users from your list and adjust your content strategy.

How to Set Up Feedback Loops:

  1. Register for feedback loops with major ISPs.
  2. Monitor feedback loop reports regularly.
  3. Remove or address subscribers who complain.


  • Provides insights into spam complaints.
  • Helps improve sender reputation.


  • Not all ISPs offer feedback loops.
  • Requires manual intervention to address complaints.



Reducing email delivery failures involves a combination of technical setups and best practices. By implementing SPF, DKIM, and DMARC, cleaning your email list, avoiding spammy content, monitoring your sending reputation, segmenting your list, using a reliable ESP, configuring bounce handling, and enabling feedback loops, you can significantly improve your email deliverability.

Summary of Pros and Cons:

  1. SPF:

    • Pros: Prevents spoofing, improves deliverability.
    • Cons: Needs updates, limited DNS lookups.
  2. DKIM:

    • Pros: Verifies authenticity, prevents tampering.
    • Cons: Technical setup, potential misconfiguration.
  3. DMARC:

    • Pros: Enhanced security, visibility into issues.
    • Cons: Requires SPF/DKIM, may block emails initially.
  4. Clean Lists:

    • Pros: Improves deliverability, reduces blacklist risk.
    • Cons: Ongoing maintenance, reduces list size.
  5. Avoid Spammy Content:

    • Pros: Improves readability and deliverability.
    • Cons: Limits promotional language.
  6. Sending Reputation:

    • Pros: Maintains good reputation, insights into issues.
    • Cons: Regular monitoring needed, requires tools.
  7. Segmentation:

    • Pros: Increases engagement, reduces unsubscribe rates.
    • Cons: Data collection and setup required, time-consuming.
  8. Reliable ESP:

    • Pros: Simplifies management, high deliverability.
    • Cons: Cost, limited customization.
  9. Bounce Handling:

    • Pros: Keeps list healthy, reduces blacklist risk.
    • Cons: Ongoing updates needed, careful handling of soft bounces.
  10. Feedback Loops:

    • Pros: Insights into complaints, improves reputation.
    • Cons: Not all ISPs offer, manual intervention required.


By following these practices, you can ensure that your emails reach your audience effectively and maintain a healthy email communication strategy.