Amazon SES emails land in spam when authentication records (SPF, DKIM, DMARC) are missing or misconfigured, sender reputation is low, engagement rates have declined, or email hygiene is poor.
To fix Amazon SES email spam issues, senders must:
- Verifying your DNS records
- Warm up sending IP
- Clean lists regularly
- Monitor deliverability metrics through the SES dashboard and tools like Warmy.io.
Amazon SES gives you enterprise-grade email delivery infrastructure at low cost. What it does not give you is a clean sender reputation, a warmed IP address, or protection against the authentication gaps that send legitimate campaigns straight to spam.
This guide covers each cause, its fix, and the SES-specific features that give you the tightest possible control over your deliverability.
Why are Amazon SES emails going to spam and how to fix it
1. Missing or misconfigured email authentication
Authentication is the first signal inbox providers evaluate. This comes before content, before reputation, before anything else. Without it, Gmail, Outlook, Yahoo, and other providers have no reliable way to confirm that your Amazon SES emails are actually coming from your domain.
Google requires all senders to have properly configured SPF and DKIM. Bulk senders, those sending 5,000+ messages per day to Gmail accounts, must also publish a DMARC record. Microsoft 365/Defender, on the other hand, uses SPF, DKIM, DMARC, and internal composite scoring as core filtering signals.
These policies, or requirements, affect every email user, including those that use Amazon SES as an email infrastructure. And if your emails are landing in spam, chances are your authentication setup is not fully aligned.
What each protocol does:
- SPF defines which mail servers are authorized to send on your domain’s behalf
- DKIM verifies the message was not altered in transit with a cryptographic signature
- DMARC enforces alignment between SPF/DKIM and your From address, and defines what happens when checks fail
How to fix this:
- Verify that SPF, DKIM, and DMARC are correctly published in your domain’s DNS
- Ensure DMARC alignment.
- Set up a custom MAIL FROM domain in Amazon SES (see SES-specific section below) to prevent SPF alignment failures
- Use Warmy’s free SPF Record Generator and DMARC Record Generator to build correctly formatted records instantly
Not sure if your SPF, DKIM, or DMARC is correctly configured for Amazon SES? Run a free Email Deliverability Test from Warmy.io: full authentication check, blacklist scan, and inbox placement report across Gmail, Outlook, and Yahoo in minutes.
2. Low email engagement rates
Global email volume reached 376.4 billion daily messages in 2025 and is forecast to reach 392.5 billion in 2026 (Statista). Inbox providers manage that volume at scale by using engagement data such as opens, replies, clicks, deletions as a key legitimacy signal.
What does this mean?
- Emails that consistently go unopened, get deleted without reading, or generate a few clicks tell Gmail and Outlook that your audience doesn’t want your content.
- That signal feeds directly into your sender reputation score and increases the likelihood of spam routing. Even when your authentication is perfect.
How to fix this:
- Warm up your domain before scaling volume. Sending at full speed from a cold domain is one of the fastest ways to get flagged
- Segment your audience and send relevant content to each group rather than blasting the same message to everyone
- Write subject lines that earn attention through genuine relevance, not urgency tricks that trigger filters
- Remove subscribers who have not engaged in 90 days because a smaller, engaged list consistently outperforms a large, disengaged one
- Include clear, valuable calls-to-action that give recipients a reason to interact
Warmy.io addresses the foundational engagement problem through automated email warmup, gradually building your sending history with authentic opens, replies, and inbox rescues that signal to inbox providers that your domain is legitimate and your mail is wanted.
3. Poor email content quality
Modern spam filters do not just flag “Buy now!!” in a subject line. They analyze the full message such as body text, HTML structure, image-to-text ratio, link destinations, and content patterns, looking for signals that match known spam campaigns.
Common content triggers include spam-loaded subject lines (excessive caps, exclamation points, trigger phrases like “Free,” “Act now,” “Guaranteed”), image-heavy emails with minimal text, broken or oversized HTML, and suspicious outbound links. When senders are not informed about these, their emails can still be sent to spam even if they are legitimate and trustworthy.
How to fix it:
- Avoid obvious spam trigger words. Run your email through Warmy’s free Template Checker before sending large-scale campaigns to catch content issues automatically
- Maintain a balanced text-to-image ratio (aim for at least 60% text)
- Ensure your HTML is clean. This means no broken tags, no embedded scripts, no inflated inline CSS
- Personalize content and segment by audience so every email feels relevant to its recipient
- Keep a plain-text alternative version of every email
4. Poor sending reputation
Amazon SES is the highway. Your domain reputation is the vehicle. But a paved road does not help a broken vehicle reach its destination.
Inbox providers track your domain’s entire sending history. This includes bounce rates, spam complaint rates, sending consistency, and recipient interaction patterns. A poor reputation means future emails face automatic scrutiny before they are even evaluated for content.
Amazon SES itself monitors your account reputation and will automatically throttle or suspend accounts that breach its thresholds:
- Bounce rate above 2% → SES may begin reducing your sending capacity
- Complaint rate above 0.1% → SES may pause your account; rates above 0.3% trigger immediate action per Google’s requirements
How to fix it:
- Keep your bounce rate below 2% by removing invalid addresses immediately and enabling Amazon SES’s built-in suppression list
- Keep spam complaint rates below 0.1% by making unsubscribing easy and visible. If recipients can’t opt out cleanly, they may report as spam instead
- Avoid sudden volume spikes. Increase sending by no more than 20–30% per week
- Regularly clean your email list to remove inactive and unengaged subscribers
Warmy’s Domain Health Hub provides visibility over DNS records, inbox placement test results, Google Postmaster metrics, and deliverability percentage. This dashboard gives senders early warning signals before declining metrics cross the thresholds that trigger SES throttling.
5. Poor email hygiene
Good infrastructure does not compensate for bad data. What does this mean? An outdated or unclean email list quietly damages your deliverability even when everything else is set up correctly.
Sending to invalid, inactive, or unengaged addresses drives up bounce rates and complaint rates simultaneously, impacting overall sender reputation.
How to fix it:
- Maintain a clean email list. Remove inactive subscribers, eliminate hard bounces immediately, and treat your list as a living system that requires regular maintenance. Hard bounces which are permanent delivery failures from invalid or non-existent addresses must be suppressed the moment they occur. Amazon SES’s built-in suppression list automates this if enabled.
- Use double opt-in. Confirming consent before adding a subscriber to your list ensures your list contains recipients who genuinely want your emails. This reduces spam complaints and improves engagement rates.
- Test and monitor deliverability regularly. Send test emails across Gmail, Outlook, and Yahoo to verify inbox placement before campaigns go live. Use Warmy’s free Email Deliverability Test for a comprehensive view of where exactly your emails are landing.
Amazon SES-specific features worth configuring
Beyond the general fixes above, Amazon SES provides infrastructure-level controls that most senders leave partially or fully unconfigured. Each one addresses a specific deliverability vulnerability.
1. Use Configuration Sets
Configuration Sets in Amazon SES let you specify how your emails are managed. This includes tracking, delivery alerts, and sending rate limits. Properly configuring these sets helps ensure your emails are sent within recommended limits, preserving a good sending reputation and lowering the risk of being marked as spam.
The real value here is segmentation. Your transactional emails (receipts, password resets, notifications) should never share a sending stream with marketing or outreach campaigns. If one stream generates complaints, Configuration Sets keep the damage contained and protect your other sending streams.
2. Set up feedback loops
Amazon SES lets you set up feedback loops (FBLs) that alert you when recipients mark your emails as spam. When enabled, Amazon SES notifies you via Amazon SNS (Simple Notification Service) any time a recipient flags an email as spam.
Without feedback loops, complaints can accumulate silently. So by the time your complaint rate is high enough to affect your account standing, the damage is already done. Acting on FBL notifications promptly (removing flagged addresses and reviewing the content that triggered complaints) helps you stay ahead of deliverability problems before they compound.
3. Handle bounces and complaints efficiently
Amazon SES provides a built‑in suppression list feature that automatically prevents future sends to addresses that have bounced or complained. Make sure it is enabled and integrated into your workflow so problematic addresses are removed without requiring manual intervention every time.
4. Set up a custom MAIL FROM domain
Amazon SES lets you set up a custom MAIL FROM domain, which lets you specify your own domain in the envelope sender (Return‑Path) address of your emails. This matters because it helps ensure alignment between your visible From address and the domain used in your SPF record, which is a key requirement for proper DMARC alignment.
Without this, SPF may pass for Amazon’s domain rather than yours, which can create an alignment mismatch when DMARC evaluates your emails.
5. Use VDM (Virtual Deliverability Manager)
Virtual Deliverability Manager (VDM) is a built‑in Amazon SES feature that provides deliverability insights and recommendations specific to your sending behavior. Rather than generic best practices, VDM analyzes your actual sending patterns and surfaces the specific issues affecting your inbox placement.
It gives you visibility into engagement metrics broken down by inbox provider, helping you identify whether a deliverability problem is isolated to Gmail or Outlook, or affecting your sending more broadly. For any sender operating at scale through Amazon SES, VDM should be one of the first features you enable. Catching a deliverability decline early is far easier than recovering from one.
How does Warmy.io help with Amazon SES emails going to spam?
Warmy.io is an AI-driven email warmup and deliverability platform that addresses the gaps Amazon SES does not cover. Specifically, IP warmup, sender reputation building, and continuous domain health monitoring.
Amazon SES gives you the infrastructure. Warmy.io builds and maintains the reputation that determines whether that infrastructure delivers to the inbox or the spam folder.
What Warmy does alongside Amazon SES:
AI-powered IP warmup. If you are using a dedicated IP with Amazon SES, warming it up correctly is critical. Sending at full volume from a cold IP signals suspicious activity to ISPs. Warmy’s Adeline AI monitors your reputation signals in real time and adjusts warmup pace dynamically so you scale volume at a rate inbox providers trust.
Real engagement signals. Warmy generates authentic interactions from real mailboxes such as opens, replies, and inbox rescues. These are not bots or simulated traffic. These signals build the positive sending history that tells mailbox providers that your domain is legitimate and your emails are wanted. Features like the Seed List and Warmup With Clicks add even more high-quality interaction signals when used alongside Warmy’s default warmup feature.
Domain Health Hub. Continuous monitoring of DNS records, inbox placement, Google Postmaster metrics, and blacklist status. This allows users to have early warning signals before metrics drift into SES throttling territory.
Combine Amazon SES infrastructure with reliable warmup from Warmy
Amazon SES is one of the most reliable and cost-effective email delivery platforms available. But sending infrastructure alone does not determine inbox placement. Your authentication setup, IP reputation, list hygiene, content quality, and ongoing monitoring all determine whether your emails reach the inbox or the spam folder.
The five causes covered in this guide (missing authentication, low engagement, poor content, damaged reputation, and weak list hygiene) are all within your control. So are the SES-specific features that give you the tightest possible grip on your deliverability: Configuration Sets, feedback loops, the custom MAIL FROM domain, and VDM.
Warmy.io fills the gap SES leaves open: the warmup, the reputation building, and the continuous monitoring that turn a correctly configured SES account into one that consistently lands in the inbox.
Start your free trial and let Warmy protect your Amazon SES inbox placement from day one.
