Summary
Even with DKIM and SPF authentication, customer service emails can be flagged as spam by Google due to a complex interplay of factors. These factors encompass technical aspects like authentication domain relevance, reply-to domain reputation, IP address reputation, and URL usage, alongside sender behavior elements like sending volume consistency, list hygiene, and engagement levels. Content-related issues, such as spam trigger words and poor formatting, also contribute, as can overly aggressive spam filters and recipient actions. Proactive reputation management, list maintenance, and content optimization are crucial for inbox placement.
Key findings
- Authentication Complexity: While necessary, DKIM and SPF are insufficient for guaranteed inbox delivery. Authentication domains, and URLs within the email all play a role in filtering.
- Sender Reputation Importance: Sender reputation, affected by engagement, complaints, spam traps, and list quality, significantly impacts deliverability.
- Content Matters: Email content, including spam trigger words, formatting, and image-to-text ratio, influences spam filtering.
- Behavioral Factors: Consistent sending volume, frequency, and good list hygiene are vital for establishing trust with email providers.
- Infrastructural Elements: Shared IP addresses and Reply-To domain reputation can negatively affect deliverability.
- Recipient Influence: Recipients marking emails as spam directly affects deliverability.
- Google Domain Association: Google can associate different domains belonging to the same company.
Key considerations
- Regular Monitoring: Continuously monitor deliverability metrics, IP/domain reputation, and spam complaints.
- Proactive Management: Actively manage sender reputation by practicing permission-based marketing and promptly addressing deliverability issues.
- List Hygiene: Implement double opt-in, regularly clean email lists, and remove inactive subscribers/spam traps.
- Content Optimization: Review email content for spam trigger words, excessive punctuation, and poor formatting.
- Sending Consistency: Maintain a consistent sending volume and frequency to establish a positive sending pattern.
- IP Control: Consider using a dedicated IP address for better control over sender reputation.
- Investigate Blacklists: Check for blacklisting and address any listing issues with appropriate remediation steps.
- Reply-To Monitoring: Make sure the reply-to address has a good reputation and is not impacting deliverability.
What email marketers say
11 marketer opinions
Even with proper DKIM and SPF authentication, customer service emails can still be flagged as spam by Google due to various factors. These include inconsistencies in sender identity (From name/address), content-related issues like spam trigger words or poor formatting, issues with sending behavior like inconsistent volume or frequency, or even overly aggressive spam filters. Other factors such as list hygiene, engagement metrics, and IP reputation also play significant roles.
Key opinions
- Sender Identity: Inconsistent 'From' names or email addresses can trigger spam filters.
- Email Content: Spam trigger words, excessive punctuation, or poor HTML can cause emails to be flagged.
- Sending Behavior: Inconsistent sending volume and frequency can trigger spam filters.
- Sender Reputation: Low engagement, spam complaints, and spam traps negatively impact sender reputation.
- IP Address: Shared IP addresses can be impacted by other senders' behavior.
- List Hygiene: Sending emails to invalid, inactive, or spam trap addresses lowers sender reputation.
- Reply-To Mismatch: A reply-to domain different from the authenticated sending domain can trigger phishing warnings.
- Overly Aggressive Filters: Sometimes, even with best practices, emails can still end up in spam due to overly aggressive filters.
Key considerations
- Sender Consistency: Ensure a consistent and recognizable sender identity across all communications.
- Content Optimization: Review email content for spam trigger words, excessive punctuation, and poor formatting.
- Sending Schedule: Maintain a consistent sending volume and frequency to establish a positive sending pattern.
- List Management: Regularly clean your email list to remove inactive subscribers and spam traps. Employ double opt-in practices.
- Engagement Monitoring: Monitor email engagement metrics (open rates, click-through rates) and address any issues promptly.
- Reputation Management: Actively monitor and manage your sender reputation, addressing any complaints or deliverability issues.
- IP Address Control: Consider switching to a dedicated IP address to have greater control over your sender reputation.
- Check Blacklists: Check if your domain is blacklisted and, if so, take steps to get removed.
Marketer view
Marketer from Email Geeks shares that Gmail sometimes displays phishing warnings when the 'reply-to' domain differs from the authenticated sending domain.
7 Nov 2023 - Email Geeks
Marketer view
Email marketer from StackOverflow explains that the content of customer service emails, even if individually written, can sometimes trigger spam filters if they contain certain keywords or phrases commonly associated with spam or phishing attempts.
7 Feb 2025 - StackOverflow
What the experts say
4 expert opinions
Even with DKIM and SPF authentication, customer service emails can be flagged as spam by Google due to various factors impacting deliverability. The authentication domains and URLs in the email can affect spam flagging, even if the sending email address is different. Furthermore, authentication alone is insufficient; list hygiene, engagement, content quality, and infrastructure issues also contribute to deliverability problems. Consistent monitoring and active management of sender reputation are key.
Key opinions
- Authentication Domains & URLs: The domains used for authentication (SPF, DKIM) and URLs in the email content can impact spam flagging, regardless of the 'From' address.
- Authentication Insufficiency: Authentication (DKIM, SPF, DMARC) is necessary but not sufficient for inbox placement.
- Reputation Factors: List hygiene, engagement levels, content quality, and infrastructure problems contribute to deliverability issues.
- Domain Association: Google can associate different domains belonging to the same company, affecting deliverability.
Key considerations
- Monitor Metrics: Continuously monitor deliverability metrics (bounce rates, spam complaints, engagement) to identify and address potential problems.
- Manage Sender Reputation: Actively manage sender reputation by maintaining a clean list, engaging content, and a healthy sending infrastructure.
- Content Scrutiny: Review email content and URLs to avoid spam triggers.
- List Hygiene: Implement strategies such as double opt-in and regular list cleaning to minimize deliverability issues.
Expert view
Expert from Word to the Wise explains that deliverability problems can be caused by poor list hygiene, low engagement, content issues, or infrastructure problems even when authentication is properly set up. They advise to monitor metrics and actively manage sender reputation.
14 Sep 2023 - Word to the Wise
Expert view
Expert from Spamresource.com highlights that authentication (DKIM, SPF, DMARC) is necessary but not sufficient for reaching the inbox. Content, reputation, and list management are also crucial factors impacting deliverability.
25 Jan 2022 - Spamresource.com
What the documentation says
4 technical articles
Even with DKIM and SPF in place, customer service emails can be flagged as spam by Google due to multiple factors. These factors include recipients marking emails as spam, spam filters identifying problematic content, a sender's IP being on a blocklist, and poor sender reputation. Maintaining a clean sending reputation through monitoring of bounce rates, spam complaints, and engagement metrics is essential, as is audience segmentation and tailored content. Additionally, the reputation of the domain in the Reply-To header can impact deliverability.
Key findings
- Authentication Insufficiency: DKIM and SPF are not enough to guarantee inbox delivery.
- Recipient Actions: Recipients marking emails as spam directly impacts deliverability.
- Spam Filters: Content and formatting can trigger spam filters, even with proper authentication.
- IP Reputation: A sender's IP address being on a blocklist significantly affects deliverability.
- Sender Reputation: Sender reputation, based on engagement and complaints, is a crucial factor.
- Reply-To Reputation: The reputation of the Reply-To header can impact deliverability.
Key considerations
- Monitor Reputation: Actively monitor IP and domain reputation to identify and address deliverability issues.
- Manage Engagement: Improve engagement through audience segmentation and tailored content.
- Avoid Blocklists: Ensure your IP address is not on any blocklists.
- Optimize Content: Review email content for spam triggers and optimize formatting.
- Monitor Reply-To: Ensure the Reply-To domain also has a good sending reputation.
Technical article
Documentation from Google Workspace Admin Help explains that emails can land in spam for several reasons even with proper authentication. These include the recipient marking it as spam, filters identifying it as spam, or the sender's IP address being on a blocklist. Content, formatting, and sender reputation also play significant roles.
14 Nov 2024 - Google Workspace Admin Help
Technical article
Documentation from SendGrid explains that to ensure deliverability, senders need to actively manage their sender reputation. This involves monitoring IP and domain reputation, keeping complaint rates low, and proactively addressing any deliverability issues. They also advise against using URL shorteners as they can negatively impact reputation.
26 Jul 2021 - SendGrid
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