How can I resolve email delivery errors due to tempfail and suspected spam?

Summary

Resolving email delivery errors related to 'tempfail' and 'suspected spam' requires a holistic approach focusing on sender reputation, technical configurations, and list management. Google's 'suspected spam' label prompts a content and infrastructure review (links, images). A key indicator is a high complaint rate, suggesting recipients don't want the emails. External factors like a company's poor reputation can contribute to spam reports. Ensure proper email authentication (SPF, DKIM, DMARC), resolve blocked IPs, use consistent sending IPs, and properly format email headers. Regularly clean email lists, segment by engagement, and remove inactive subscribers. When facing 'tempfail' errors, check server logs, network connectivity, and configure proper retry mechanisms for greylisting. Gradually warm up new IPs and consider dedicated IPs for high-volume sending. Address technical issues such as reverse DNS records and monitor your domain reputation.

Key findings

  • Sender Reputation is Key: A good sender reputation is critical, influenced by IP reputation, domain reputation, and recipient engagement.
  • Email Authentication is Mandatory: Implementing SPF, DKIM, and DMARC is essential to verify sender identity and prevent spoofing.
  • List Hygiene is Crucial: Regularly cleaning email lists, segmenting, and removing unengaged subscribers improve deliverability.
  • Complaint Rate is a Direct Indicator: A high spam complaint rate signals recipients don't want the email and negatively impacts deliverability.
  • Technical Setup Matters: Properly configured DNS records, email headers, and server retry mechanisms for transient errors are vital.

Key considerations

  • Monitor Logs and Metrics: Regularly check server logs for rate limiting, authentication failures, and transient errors, and monitor metrics like complaint rates.
  • Validate Email Content: Review email content, links, and image hosting to avoid spam triggers.
  • Implement Double Opt-in: Use double opt-in to ensure subscribers actively want to receive emails.
  • Gradual IP Warming: Gradually warm up new IP addresses by starting with low sending volumes and increasing over time.
  • Address External Reputation Issues: Address any negative publicity or reviews affecting the overall company/domain reputation as it can influence email deliverability.
  • Stop Mailing Uninterested Recipients: Prioritize sending emails only to engaged recipients and promptly remove those who haven't interacted recently or have complained.

What email marketers say
10Marketer opinions

To resolve email delivery errors related to 'tempfail' and 'suspected spam,' it's crucial to focus on improving and maintaining a positive sender reputation. This involves authenticating emails using SPF, DKIM, and DMARC, actively managing email lists by removing inactive subscribers and avoiding spam traps, and carefully monitoring and reducing spam complaint rates. Gradual IP warming, optimizing email HTML code, personalizing content, avoiding spam trigger words, and using dedicated IPs for high-volume sending are also beneficial strategies.

Key opinions

  • Sender Reputation: Improving and maintaining a positive sender reputation is essential for deliverability.
  • Email Authentication: Using SPF, DKIM, and DMARC helps to authenticate emails and improve deliverability.
  • List Management: Actively managing email lists by removing inactive subscribers is important.
  • Spam Complaints: Reducing spam complaint rates is crucial for maintaining a good sender reputation.
  • Content Optimization: Optimizing email content and avoiding spam trigger words improves deliverability.

Key considerations

  • Log Monitoring: Regularly check logs for messages related to rate limiting and other delivery issues.
  • Authentication Setup: Ensure SPF, DKIM, and DMARC records are correctly configured.
  • List Segmentation: Segment email lists based on engagement to improve relevance.
  • IP Warming: Gradually warm up new IP addresses to build a positive reputation.
  • Dedicated IPs: Consider using a dedicated IP address for high-volume sending to manage reputation independently.
Marketer view

Email marketer from Mailjet explains that improving your sender reputation is key. Ensure your sending IP addresses and domain have a good reputation by authenticating your emails with SPF, DKIM, and DMARC.

September 2023 - Mailjet
Marketer view

Email marketer from StackOverflow explains that to reduce spam scores, optimize your email's HTML code, avoid excessive use of images without alt text, and ensure your email is mobile-friendly.

October 2023 - StackOverflow
Marketer view

Email marketer from EmailOctopus explains that a high spam complaint rate negatively impacts deliverability. They recommend using double opt-in, segmenting lists, and providing clear unsubscribe options to reduce complaints.

November 2022 - EmailOctopus
Marketer view

Email marketer from Quora shares to avoid spam trigger words in your subject lines and email content. Also test emails with tools like Mail-Tester or GlockApps to check for spam triggers.

March 2021 - Quora
Marketer view

Email marketer from Email Geeks shares to look at the logs for messages such as rate limiting due to unusual mail rates, and to slow down sending or check list quality/inactive contacts.

August 2023 - Email Geeks
Marketer view

Email marketer from Litmus explains that regularly cleaning your email list is crucial for maintainability. Remove inactive subscribers and those who haven't engaged in a while to boost deliverability.

March 2021 - Litmus
Marketer view

Email marketer from Reddit shares that warming up your IP address gradually is crucial, especially when starting with a new domain or IP. Start with small volumes and gradually increase over time to build a good reputation.

September 2021 - Reddit
Marketer view

Email marketer from HubSpot shares that to improve deliverability, clean your email lists regularly, personalize your email content, and avoid using spam trigger words in your subject lines and body.

January 2025 - HubSpot
Marketer view

Email marketer from Sendinblue explains that maintaining a good sender reputation requires consistent sending volume, avoiding spam traps, and actively managing your email list by removing inactive subscribers.

December 2021 - Sendinblue
Marketer view

Email marketer from MailerCheck says that to consider using a dedicated IP address, especially if you are sending a high volume of emails. This allows you to manage your sender reputation independently of shared IP addresses.

February 2025 - MailerCheck

What the experts say
7Expert opinions

To resolve email delivery errors due to 'tempfail' and 'suspected spam', it's crucial to understand the underlying causes. 'Suspected spam' indicates Google is evaluating the email's legitimacy, so check links, image hosting, and list quality. A high complaint rate suggests recipients don't want the mail. External factors like a company's poor reputation can contribute to spam reports. Technical aspects like greylisting require proper server retry configurations, and authentication failures need accurate SPF, DKIM, and DMARC setup. Fundamentally, stop mailing uninterested recipients and maintain list hygiene through regular cleaning and segmentation.

Key opinions

  • Recipient Desire: High complaint rates often mean recipients don't want your emails; address this core issue.
  • Reputation Impact: A poor overall company reputation can negatively impact email deliverability.
  • Technical Configuration: Proper configuration of SPF, DKIM, DMARC and retry settings for greylisting is critical.
  • Google's Spam Detection: "Suspected spam" signals a need to review content and infrastructure details (links, images).

Key considerations

  • List Hygiene: Regularly clean and segment your email list based on engagement.
  • Domain Reputation: Monitor your overall domain reputation and address any underlying issues (not just email-related).
  • Authentication Validation: Validate SPF, DKIM, and DMARC records using online tools.
  • Content Review: Carefully review email content, links, and image hosting to identify potential spam triggers.
  • Greylisting Retry: Configure email servers to properly retry sending emails after greylisting related temporary failures.
Expert view

Expert from Email Geeks advises to stop mailing people who don't want to hear from you.

July 2023 - Email Geeks
Expert view

Expert from Spamresource.com explains that if you are seeing a tempfail error due to greylisting (a technique used by mail servers to temporarily reject emails from unknown senders) ensure that your sending server retries sending the email after a delay as per the SMTP standards. Also, make sure that your server is properly configured for retries.

March 2024 - Spamresource.com
Expert view

Expert from Spamresource.com says to resolve tempfail errors due to authentication problems (SPF, DKIM, DMARC), check your DNS records to make sure they are set up correctly. Use online tools to validate the syntax and correctness of your SPF, DKIM, and DMARC records.

December 2024 - Spamresource.com
Expert view

Expert from Email Geeks states that a 1% complaint rate indicates recipients don't want the mail, and the temp failing is Google acknowledging this.

May 2023 - Email Geeks
Expert view

Expert from Email Geeks points out that Crystal Travel has a terrible reputation unrelated to email, suggesting the spam reports might stem from this.

February 2022 - Email Geeks
Expert view

Expert from Wordtothewise.com suggests regularly cleaning your email list and segmenting by engagement to maintain a good sender reputation and prevent being marked as spam. Actively remove unengaged recipients.

April 2024 - Wordtothewise.com
Expert view

Expert from Email Geeks explains that "suspected spam" means Google suspects the mail is spam and is slowing down delivery to decide if it is spam, and suggests checking links, image hosting domains, and subscriber list quality.

February 2025 - Email Geeks

What the documentation says
5Technical articles

To resolve email delivery errors stemming from 'tempfail' and 'suspected spam,' a multi-faceted approach is necessary. This includes resolving blocked IP addresses, maintaining consistent sending IP addresses, minimizing complaint rates, ensuring correctly formatted email headers, and confirming the presence of reverse DNS records. Implement email authentication protocols like SPF, DKIM, and DMARC to verify sender identity and prevent spoofing. Regularly check your IP and domain against email blacklists and promptly address any listings. Remember that 'tempfail' indicates a transient error requiring server log analysis and retry mechanisms.

Key findings

  • IP Reputation: Blocked or inconsistent IP addresses negatively impact deliverability.
  • Email Authentication: SPF, DKIM, and DMARC are essential for verifying sender identity.
  • Blacklist Monitoring: Regularly checking blacklists is crucial for proactive issue resolution.
  • Technical Standards: Correctly formatted email headers and reverse DNS records are vital for trust.
  • Transient Errors: "Tempfail" indicates a transient server-side issue requiring investigation and automated retries.

Key considerations

  • IP Management: Implement policies to maintain consistent sending IP addresses.
  • Header Formatting: Adhere to email header formatting standards.
  • Complaint Rate: Proactively manage and minimize email complaint rates.
  • DNS Records: Verify and maintain correct reverse DNS records.
  • Blacklist Removal: Have a plan in place to promptly address and resolve any blacklist listings.
  • Server Logs: Regularly check the server logs to identify the cause of any transient errors.
Technical article

Documentation from Microsoft explains that to prevent email from being marked as junk, ensure your sending server has reverse DNS records, avoid URL shorteners, and monitor your domain reputation through their Sender Support services.

January 2022 - Microsoft
Technical article

Documentation from Google explains that to fix email delivery issues, resolve any blocked IP addresses, use consistent IP addresses for sending, keep complaint rates low, and ensure properly formatted email headers.

June 2024 - Google Workspace Admin Help
Technical article

Email Documentation from GlockApps shares that you should regularly check your IP address and domain against email blacklists. If you are on a blacklist, work to get removed by following their specific procedures.

September 2023 - GlockApps
Technical article

Documentation from SparkPost explains that implementing email authentication protocols like SPF, DKIM, and DMARC is essential for verifying your sender identity and preventing spoofing.

August 2023 - SparkPost
Technical article

Documentation from RFC explains that "Tempfail" indicates a temporary failure, it means the server encountered a transient error and the message might be delivered later. Check server logs, network connectivity, and retry sending.

September 2023 - RFC