Summary
Even with a low spam rate, emails can still land in the spam folder due to a confluence of factors. These include IP reputation issues (especially on shared IPs), missing or incorrect email authentication (SPF, DKIM, DMARC), content triggers in the email body, poor list hygiene practices (including spam traps and outdated addresses), low engagement rates, sudden increases in sending volume, inconsistent sending patterns, misleading sender information in the 'from' field or subject line, being listed on DNSBLs, and external factors like increased user scrutiny. Sender reputation is crucial and built over time, affected by many elements beyond just the complaint rate. Proper list acquisition, management and sending practices are also essential. Validate engagement rate as a high unsub/abuse rate can be expected.
Key findings
- IP Reputation: Poor IP reputation (especially on shared IPs) leads to spam filtering.
- Authentication: Missing/incorrect SPF, DKIM, DMARC flags emails as suspicious.
- Content Triggers: Spam filters analyze content for trigger words and poor HTML-to-text ratio.
- List Hygiene: Poor list hygiene means spam traps and invalid addresses affect reputation.
- Engagement: Low engagement (opens, clicks) indicates low value and leads to spam filtering.
- Sending Volume: Drastic volume increases trigger spam filters.
- Sending Patterns: Inconsistent sending negatively impacts deliverability.
- Sender Information: Misleading sender names/subject lines cause spam reports.
- DNSBL Listing: Being listed on DNSBLs results in deliverability issues.
- External Factors: Increased user scrutiny and previous complaints can cause spam rate spikes.
- Poor Documentation of List aquisition: Poorly documented list aquisition can have unengaged recipents or spam traps.
- Validate Engagement: Validate engagement rate if it is close to 2X than usual as a high unsub/abuse rate can be expected.
Key considerations
- Monitor IP Reputation: Regularly check and address IP reputation issues.
- Implement Authentication: Ensure correct SPF, DKIM, DMARC configuration.
- Optimize Content: Avoid trigger words, excessive links; improve HTML-to-text ratio.
- Clean Email Lists: Regularly remove invalid/unengaged addresses.
- Improve Engagement: Create engaging content to boost opens and clicks.
- Warm Up IPs: Gradually increase volume when starting with a new IP/domain.
- Maintain Consistency: Establish and maintain a regular sending schedule.
- Be Transparent: Use clear and accurate sender names/subject lines.
- Check DNSBLs: Regularly check if your IP/domain is listed on DNSBLs.
- Monitor Spam Complaints: Consider what was sent just before the spike date that might have caused more complaints than usual.
- Document List Acquisition: Document your list acquisition methods.
What email marketers say
11 marketer opinions
Even with a low reported spam rate, emails can still land in the spam folder due to a variety of factors. These include IP reputation, missing or incorrect email authentication, content triggers, poor list hygiene, low engagement, sudden increases in sending volume, inconsistent sending patterns, misleading sender information, and the use of shared IP addresses. External factors, such as increased user scrutiny and spam trap hits, also contribute to this issue.
Key opinions
- IP Reputation: A poor IP reputation, especially on shared IPs, can lead to spam filtering regardless of spam rate.
- Authentication: Missing or incorrect SPF, DKIM, and DMARC records flag emails as suspicious.
- Content Triggers: Spam filters analyze content for trigger words, excessive links, and HTML-to-text ratio.
- List Hygiene: Outdated or poorly maintained email lists contain spam traps and invalid addresses.
- Engagement: Low open and click rates signal low value and lead to spam filtering.
- Sending Volume: Drastic increases in sending volume trigger spam filters.
- Sending Patterns: Inconsistent sending patterns negatively impact deliverability.
- Sender Information: Misleading sender names and subject lines cause spam reports.
- Shared IPs: Using a shared IP ties your reputation to other senders.
- User Scrutiny: Increased user scrutiny and inbox cleaning can lead to higher spam reports.
Key considerations
- Monitor IP Reputation: Regularly check your IP reputation and address any issues promptly.
- Implement Authentication: Ensure SPF, DKIM, and DMARC records are properly configured.
- Optimize Content: Avoid spam trigger words, excessive links, and ensure a good HTML-to-text ratio.
- Clean Email Lists: Regularly remove invalid or unengaged addresses from your email list.
- Improve Engagement: Create engaging content that encourages opens and clicks.
- Warm Up IPs: Gradually increase sending volume when starting with a new IP or domain.
- Maintain Consistency: Establish and maintain a regular sending schedule.
- Be Transparent: Use clear and accurate sender names and subject lines.
- Consider Dedicated IP: If possible, use a dedicated IP for more control over your sender reputation.
- Engagement Validation: Validate engagement rate if it close to 2X than usual as a high unsub/abuse rate can be expected.
Marketer view
Email marketer from Reddit user u/EmailExpert explains that spam filters analyze email content. Using spam trigger words, excessive links, or a poor HTML-to-text ratio can lead to spam placement, regardless of the overall spam rate.
13 Sep 2022 - Reddit
Marketer view
Email marketer from Gmass explains that inconsistent sending patterns can negatively impact deliverability. Maintain a regular sending schedule to establish a positive sending reputation.
8 Dec 2024 - Gmass
What the experts say
6 expert opinions
Even with a low spam rate, email deliverability can be affected by factors such as low sending volume combined with prior complaints, the content of recent mailings, changes in user behavior, sender reputation, authentication issues, blacklistings, list acquisition methods, list hygiene, sending frequency, and the use of shared domains and IPs. A holistic view of these elements is crucial for understanding and resolving deliverability problems.
Key opinions
- Low Volume Impact: Zero email volume combined with previous complaints can cause spam rate spikes.
- Content Sensitivity: The content of recent mailings can trigger complaints.
- User Behavior Changes: Changes in user behavior, such as increased scrutiny or boredom, can affect spam reports.
- Sender Reputation: Poor sender reputation, even with a low complaint rate, leads to deliverability issues.
- Authentication and Blacklists: Lack of authentication or being on blocklists damages deliverability.
- List Acquisition: Poorly documented list acquisition can introduce spam traps and unengaged recipients.
- List Management: Improper list management and hygiene practices lead to low engagement.
- Sending Frequency: Sending too often or too little can damage deliverability.
- Shared Infrastructure: Sending from shared domains and IPs can negatively affect deliverability.
Key considerations
- Analyze Recent Content: Review the content of recent mailings for potential triggers.
- Evaluate User Behavior: Consider changes in user behavior that could affect spam reports.
- Improve Sender Reputation: Take steps to improve sender reputation, such as authentication and list hygiene.
- Document List Acquisition: Ensure thorough documentation of list acquisition methods.
- Implement List Hygiene: Practice proper list management and hygiene to maintain engagement.
- Optimize Sending Frequency: Find the optimal sending frequency for your audience.
- Evaluate Infrastructure: Assess the impact of shared domains and IPs on deliverability.
- Consider Recent Complaints: Consider what was sent just before the spike date that might have caused more complaints than usual.
Expert view
Expert from WtotheWise, Karen Talavera, responds that even with permission based marketing, if you email too often or too little you can damage deliverability because people forget about you and mark you as spam. Sending from shared domains and IPs can also cause deliverability issues.
20 Jul 2021 - WtotheWise
Expert view
Expert from Email Geeks suggests to consider what was sent just before the spike date that might have caused more complaints than usual.
18 Apr 2023 - Email Geeks
What the documentation says
4 technical articles
Even with a low spam rate, emails can be filtered as spam due to factors identified in official documentation. A small number of spam complaints significantly impact deliverability, especially with low email volume. Incorrect or missing reverse DNS (rDNS) records and individual users marking emails as junk also negatively affect sender reputation. Furthermore, being listed on a DNSBL due to spam-like activity, regardless of the reported spam rate, can cause deliverability issues. Proactive list cleaning and regular checks of rDNS records and DNSBL listings are necessary.
Key findings
- Low Complaint Threshold: Even a small number of spam complaints can negatively impact deliverability, especially with low sending volume.
- Missing rDNS: Missing or incorrect reverse DNS (rDNS) records can cause deliverability issues.
- User Junk Marking: Users marking emails as junk negatively impacts sender reputation.
- DNSBL Listing: Being listed on a DNSBL due to spam-like activity causes deliverability issues.
Key considerations
- Proactive List Cleaning: Implement proactive list cleaning strategies to minimize spam complaints.
- Verify rDNS Records: Ensure correct configuration of reverse DNS (rDNS) records.
- Monitor Reputation: Monitor your sender reputation and address issues raised by feedback loops.
- Check DNSBL Listings: Regularly check if your IP or domain is listed on a DNSBL.
Technical article
Documentation from Spamhaus explains that being listed on a DNSBL (DNS-based Blackhole List) due to spam-like activity, even if the overall spam rate appears low on your end, can cause significant deliverability issues. Check if your IP or domain is listed.
24 Mar 2023 - Spamhaus
Technical article
Documentation from Microsoft states that users individually marking emails as 'junk' or blocking the sender contributes negatively to your reputation, leading to the spam folder even with a low overall spam rate reported via feedback loops.
3 Dec 2022 - Microsoft
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