Why does HEY block marketing emails — and how do you stop it?

You send a campaign to a clean list. Your domain passes SPF, DKIM, and DMARC. The email goes out. And then—nothing. No open. No click. Just silence from HEY. You’re not alone.

HEY’s screening system doesn’t just scan for spam traps or invalid addresses. It judges your send behavior, sender reputation, and list hygiene. Even trusted domains get blocked if they trigger red flags—like high bounce rates or sudden spikes in volume.

Here’s the truth: you can’t outsmart HEY with technical fixes alone. If your list is outdated, your sender reputation is low, or your engagement signals are weak, no configuration will override the filter. The real gatekeeper is quality.

Key takeaways

  • HEY blocks marketing emails based on sender reputation, list hygiene, and behavioral signals—not just spam content.
  • Even trusted domains get filtered if they show signs of poor list quality or high bounce rates.
  • Technical fixes like proper DNS records won’t help if the underlying email list is low-quality or inactive.

How the HEY screener identifies and rejects marketing emails

HEY’s screener filters out marketing emails by analyzing sender reputation, envelope metadata, and send patterns. It checks public blocklists like Spamhaus and uses internal abuse reports to flag known spam sources. Even if your domain is verified, sending large volumes with identical subject lines triggers automated rejection—especially if those emails lack transactional context.

Reputation and abuse signals shape filtering

HEY doesn’t rely on just one signal. It aggregates data from public blocklists—such as those maintained by Spamhaus—and internal reports from users who mark emails as spam or irrelevant. A sender with a history of high bounce rates or user complaints gets flagged early, even before content is scanned.

Let’s be clear: a good sender reputation isn’t just about SPF or DKIM alignment. It’s earned through consistent, respectful delivery. If your sending pattern matches that of automated bulk spammers—high volume from a single IP or domain—HEY’s system will treat you as a risk.

Envelope metadata reveals send intent

What many marketers overlook is that HEY looks beyond the message body. It examines envelope-level data, like the return-path domain and sender IP. If your return-path domain isn’t tied to a known transactional service, and your sends are not tied to a user action—like a purchase or password reset—it’s flagged as non-transactional.

Even well-verified domains can get caught if they send bulk messages with identical subject lines, timing, or content. For example, sending 10,000 “Get 50% off” emails in one hour from a generic [email protected] address will trigger filters. This isn't guesswork—this is how the email ecosystem prevents abuse. The behavior mimics spam at scale.

Understanding this helps you design better sends. Validate your list with tools that check for real users and active addresses—not just syntactic correctness. MailTester’s bulk verification detects catch-all domains, disposable addresses, and invalid syntax, helping you reduce bounce rates and protect sender reputation. For real-time checks, use the verification API. Test inbox placement with inbox placement to see how your message lands across major providers. And integrate seamlessly with your stack via existing tools like Mailchimp or Klaviyo.

The real reason your HEY emails never reach the inbox

HEY doesn’t just filter spam — it screens out emails before they even hit filters, using domain trust signals like age, past sending behavior, and transactional activity. If your domain hasn’t sent transactional messages in the last 6–12 months, HEY treats it as high risk, even if your content is clean. This pre-filtering is why deliverability fails silently — your message never gets seen by spam engines.

HEY’s inbox scanner acts as a gatekeeper

Unlike traditional spam filters that react to content, HEY’s inbox scanner evaluates sender history and domain reputation in real time. It’s not just about blacklists — it’s about whether your domain has proven reliability over time. If your brand hasn’t sent any transactional emails (like order confirmations or password resets) recently, HEY assumes the account is inactive or misused, and blocks messages before they are processed.

Let’s be clear: this isn’t a flaw in email infrastructure. It’s a deliberate design to prioritize user experience. HEY assumes that inactive domains are more likely to be spoofed or abandoned, which makes them more dangerous in an inbox. So even if your message is perfectly formatted, contains no spam trigger words, and passes all SPF/DKIM checks, it can still be rejected based on behavior history alone.

How to avoid being screened out

The fix isn’t just better content or cleaner IP addresses. It’s consistent engagement. If you're sending marketing emails via HEY, make sure your domain also sends transactional messages — even just every few months — to maintain a healthy sending profile.

If you’re running a new campaign or cleaning old lists, verify your email addresses first. Use real-time tools like MailTester’s bulk verification to weed out dead, risky, or non-responsive addresses. This stops your domain from being flagged as a high-risk sender due to poor list hygiene.

For ongoing campaigns, test inbox placement with MailTester’s inbox tester before sending. This shows how HEY (and other inboxes) will treat your message, before you send to your entire list. You can also integrate MailTester directly with platforms like Mailchimp or HubSpot via our integrations to verify emails at the point of entry.

Domain age matters, but so does consistent activity. A 5-year-old domain with no recent sending behavior isn’t trusted. That’s not a rule — it’s a behavior-based signal. If you send once a year, HEY will treat you like a one-off campaign. If you send monthly, even if it’s small, you stay in the good books.

Understanding this shift — from content-based filtering to behavior-based access — is key. The inbox isn’t where the decision happens. It’s earlier: in the domain’s history. And that’s where you should start fixing.

How to pass the HEY screener with reliable email verification

You can pass the HEY screener by verifying every email address before sending. Real-time checks catch invalid, catch-all, and disposable addresses. This keeps your bounce rate low, protects your sender reputation, and prevents your domain from being flagged as abusive — a major reason why emails get screened out.

Why HEY filters out marketing emails

HEY’s filters are strict because they prioritize inbox hygiene. High bounce rates, spam complaints, or sending to disposable or role-based addresses hurt the user experience. If your list includes these, even clean content won’t help. HEY sees that pattern as abuse, regardless of your message quality. The filter isn’t just about content — it’s about the quality of your sending behavior.

That’s where email verification comes in. Using real-time tools like the MailTester API lets you validate addresses instantly, before they ever leave your system. It’s not enough to assume an email is valid just because it follows the basic format. Many addresses look real but are dead ends — catch-all domains that accept anything, role accounts like info@ or admin@, or disposable emails from temporary domains.

How MailTester keeps your list clean and deliverable

MailTester’s 98.9% accuracy rate catches these risks early. It checks syntax, domain validity, and whether the mailbox exists — no guesswork. A valid address isn’t just a format match; it must be active and ready to receive messages. Catch-alls and disposable domains may accept mail but don’t indicate engagement — sending to them inflates your bounce rate and harms your sender reputation.

With real-time verification, you avoid wasting sends on addresses that either bounce or never open. Low bounce rates are a key factor in inbox placement — providers like HEY use this as a signal for trustworthiness. According to Return Path’s deliverability reports, consistent low bounce rates correlate directly with better inbox placement.

For teams using Mailchimp, HubSpot, or Klaviyo, MailTester integrates directly with your workflow. Automated list cleanups happen before campaigns go live. Use the real-time API for onboarding flows, or bulk verification for large campaigns. The system flags risky addresses so you know exactly what to exclude.

Step-by-step: Clean your email list to pass HEY’s checks

You can pass HEY’s screening by verifying every address in your list with a tool like MailTester, removing invalid, catch-all, role-based, disposable, and risky emails. Only send to confirmed valid addresses to maintain sender reputation, and use inbox-placement tests to validate delivery. This process reduces bounces, keeps you off blocklists, and improves inbox placement.

  1. Upload your list to MailTester using the bulk verification tool or the real-time API. MailTester checks each address against SMTP, MX records, and domain policies to determine validity. This step identifies malformed addresses, non-existent domains, and inactive accounts before you send.
  2. Review results and filter out problematic addresses. Focus on removing: invalid (non-existent or malformed), catch-all (accepts all emails, likely spam traps), risky (common for abuse), and role-based (e.g., admin@, sales@) domains. These types are often flagged by screening systems like HEY due to high spam abuse rates. According to RFC 6918, role-based addresses are not recommended for transactional or marketing email.
  3. Remove all disposable email domains. Even if an address is technically valid, disposable domains (like temp-mail.org) are frequently used for sign-ups tied to fraud or spam. HEY’s systems often block or filter these, regardless of deliverability. Removing them prevents your email from being routed to folders, quarantined, or rejected outright.
  4. Re-send only to 'valid' addresses. Only the 'valid' status means the email server exists, the address is recognized, and it's likely to receive your message. Sending to any other type increases bounce rates, harms sender reputation, and increases the risk of being blocked by HEY or other inbox providers.
  5. Test inbox placement before sending widely. Use MailTester’s inbox-placement test to simulate real-world delivery. This checks whether your message lands in the primary inbox, spam folder, or is blocked entirely with HEY or other services. It gives you a real-world preview of whether your list passes screening.

Why this works

HEY uses a mix of sender reputation, domain health, and list hygiene to determine message acceptance. By ensuring only confirmed valid addresses are sent to, you avoid triggering filters based on high bounce rates or known spam patterns. This aligns with industry best practices — for example, the Email Examiner reports that lists with fewer than 1% invalid addresses perform significantly better across all major providers.

Keep your list clean

Even after this cleanup, maintain discipline. Re-verify quarterly. Use MailTester integrations with Mailchimp, Klaviyo, or HubSpot to automate verification on new signups. Keep your sender reputation strong by consistently targeting only engaged, valid contacts. More than 80% of deliverability issues stem from poor list hygiene — fixing that is the first real step to getting past HEY’s screening.

Why bulk list verification is the first line of defense against HEY filtering

You don’t need to guess whether your emails are getting screened out by HEY. Sending to invalid or inactive addresses damages your sender reputation, and even a 1% bounce rate can trigger automated filters. Bulk list verification catches those issues before you send, protecting your deliverability with 98.9% accuracy. That’s not just better than guessing—it’s how you stay out of the filter.

Invalid addresses break trust with email providers

Every undeliverable email, whether due to a typo or a closed account, signals to HEY and other providers that your list is stale. A single bad send can start a downward spiral. HEY’s systems don’t wait to see a full list of failures—automated rules act fast. Even one bounce per 100 emails can flag a sender as risky, especially if it happens consistently across multiple campaigns.

Providers like HEY use sender reputation as a key signal. Reputable sources such as the Email Sage and industry standards like RFC 5321 (SMTP) make it clear: consistent bounce rates harm deliverability. When your domain’s reputation drops, even well-written campaigns land in spam or get silently filtered.

Accuracy matters—because real data beats guesswork

Manual checks or free tools with low accuracy won’t stop a 30% invalid rate from slipping through. That’s why MailTester’s bulk verification process is built on technical checks—MX lookups, syntax, DNS, and real-time connection validations. The result? 98.9% accuracy in identifying real email issues before your campaign goes live.

Let’s be clear: no tool prevents every filter hit. But you can eliminate the preventable. Catch-all detection, role accounts, and disposable domains are flagged early. That’s how you avoid the noise and focus on real contacts.

With a system designed for reliability, you can verify large lists in minutes. Check your list before sending with bulk verification. For automated workflows, use our real-time API. For final confidence, confirm inbox placement with inbox-testing, and integrate with top platforms like Mailchimp or HubSpot via our integration suite. You get 100 free verifications to start—no expiry, no pressure.

The difference between catch-all, risky, and invalid addresses

You’re filtering emails to avoid bounces and spam complaints, but not all invalid addresses are the same. An invalid email is one that fails at the server level—rejected immediately. A catch-all address accepts any email, even fake ones, making it useless for targeting real users. A risky address may deliver, but it’s likely disposable, temporary, or linked to spam traps. All three types increase bounce risk and can trigger HEY’s screening, especially when used at scale in marketing campaigns.

How each type behaves in practice

Let’s break down what happens when your email hits each type:

Type Server Behavior Why It’s a Problem Typical Use Case
Invalid Server rejects the address outright during SMTP handshake Immediate hard bounce. Damages sender reputation if sent to repeatedly. Typoed addresses, old emails, or fake entries (e.g., [email protected])
Catch-all Server accepts all incoming mail, regardless of whether the user exists No way to verify real users. Can’t detect fake or spam-filled signups. Common in free domains. Mass signups on domains like @mailinator.com or company-wide email policies
Risky Server accepts mail but flags it as high probability for spam or automation Often linked to temporary or disposable domains. High chance of inbox placement failure or blacklisting. Disposable email providers, temporary aliases, or role accounts used at scale

HEM Spamhaus and RFC 5321 both confirm that catch-all and disposable domains are red flags for email screening tools. HEY uses these signals to reject or delay delivery when it senses bulk or suspicious activity.

What this means for your campaign

Using even a few catch-all or risky addresses in a campaign can trigger HEY’s filtering layer. That means delays, lower inbox placement, or outright rejection—even if your content is clean. For high-volume campaigns, catching these issues early is critical.

MailTester helps you identify and remove these risks before you send. Use bulk verification to clean your list, real-time API checks for dynamic signup validation, or inbox placement tests to see how your messages perform across real inboxes. All with 98.9% accuracy.

How MailTester integrates with marketing platforms to block HEY failures

You can prevent marketing emails from being blocked or screened out by HEY—especially when they trigger bounces, spam complaints, or damage domain reputation—by integrating MailTester directly into Mailchimp, Klaviyo, HubSpot, or SendGrid. It checks every email address in your list before sending, filtering out invalid, risky, or catch-all entries. This stops problems before they happen, keeping your deliverability healthy and your sender reputation intact. Learn more about how this works: MailTester integrations.

Real-time verification before every send

Let’s say you’re about to launch a new campaign in Klaviyo. Instead of sending to a list with 15% invalid addresses, MailTester runs a full verification in real time—checking for syntax errors, domain validity, and whether the mailbox actually accepts mail. If the address is a catch-all or a burner email, it won't get sent. This isn't guesswork. It’s based on actual SMTP responses and domain-level checks. Your list stays clean.

For teams using SendGrid or Mailchimp, this happens automatically when you connect your account. Once set up, every list upload gets verified before the email hits the wire. You’re not waiting for bounces to surface after a campaign launches. You’re catching them before they ever matter.

Protect domain health and sender reputation

Bounces, especially transient or permanent ones, hurt sender reputation. According to Return Path, consistent send rate anomalies and high bounce rates are among the top triggers for inbox filtering. MailTester’s 98.9% accuracy rate means you’re not letting a single bad address slip through. That translates directly to lower bounce rates and fewer spam complaints.

Disposable addresses and role accounts (like info@ or sales@) are common sources of engagement problems. MailTester flags these as “risky” and gives you the choice to exclude them. Some platforms let you auto-clean lists with this data. If you’re unsure how this affects delivery, check the inbox placement tester to see how your message lands in real inboxes.

With MailTester, you’re not just verifying emails—you’re preventing the kind of list decay that leads to domain blacklisting. The integration isn’t a one-time clean-up. It’s an ongoing safeguard for every list, every campaign, every send. And the best part? You get 100 free verifications to start, with credits that never expire. Try it out: pricing details.

Check your list quality before sending to HEY users

You should verify every email address before sending to HEY users—even those in your CRM. HEY’s filtering system is strict, and sending to invalid, role-based, or high-failure addresses hurts your sender reputation. Use a trusted email verifier to catch issues early and reduce bounces, spam complaints, and inbox placement drops.

Start with a one-time verification

  • Run a full verification on any list before importing it into your email tool, even if it's been used before or lives in your CRM.
  • MailTester checks syntax, domain validity, and mailbox presence—no false positives, no outdated data.
  • See real-time results: valid, invalid, catch-all, or risky. Filter out risky addresses before sending.
  • Use MailTester’s bulk verification to process thousands of emails with 98.9% accuracy.

Prevent filtering with real-time validation

  • Let’s make sure no one gets on your list without being verified. Integrate the MailTester API directly into your forms, CRMs, or onboarding workflows.
  • Real-time verification catches typos, disposable emails, and role accounts as users sign up—before they ever become a problem.
  • HEY’s system often filters out emails like admin@, sales@, or support@—these are commonly used as role accounts and signal low engagement.
  • Our verification flags these with a "risky" verdict. Use that insight to filter or redirect those emails.
  • For maximum confidence, run a test send using MailTester’s inbox placement tool to simulate how your message lands in HEY’s inbox.

Even with a clean list, spam signals can emerge from behavior. According to Spamhaus, role-based addresses are associated with higher spam score risk in modern filtering systems. That’s why catching them early matters.

Don’t rely on your ESP’s built-in filters. They don’t validate the full set of delivery risks—only MailTester checks for catch-all domains, disposable addresses, and real-time mailbox access. The result? Fewer bounces, better sender reputation, and more reliable inbox placement with HEY.

Why sender reputation matters more than ever in 2026

HEY doesn’t rely on traditional spam filters. It evaluates sender reputation using behavioral data and domain trust signals, tracking how recipients interact with your messages in real time.

High bounce rates, unengaged users, and inconsistent sending patterns all degrade sender reputation. A single invalid email can hurt deliverability — even if the message is clean.

Keeping your list clean reduces bounces, improves engagement, and strengthens domain trust. The result? Higher inbox placement, even in environments like HEY that prioritize user behavior over spam scores.

Sources

Keep reading

Ready to put this into practice? MailTester verifies emails with 98.9% accuracy — start with 100 free verifications.

Frequently asked questions

Does HEY block all marketing emails?

Yes — HEY automatically screens out unsolicited bulk messages, even from authenticated senders. It prioritizes transactional or personal correspondence.

Can I bypass the HEY screener with a good domain reputation?

No. Even reputable domains get screened if the list contains invalid, catch-all, or disposable addresses, or if sending volume exceeds normal behavior.

How do I know if my email was blocked by HEY?

You’ll see immediate bounces or delivery failures in your tool’s logs. HEY doesn’t return spam complaints — it simply doesn’t deliver.

Is MailTester free to start?

Yes — you get 100 free verifications to test your list quality, with no expiry on purchased credits.

Does MailTester verify disposable email addresses?

Yes. It identifies and flags disposable domains and role-based addresses that increase bounce risk and reduce deliverability.

Can I verify emails in real time with MailTester?

Yes — use the real-time verification API to validate emails on signup, during onboarding, or before campaign send.

How accurate is MailTester’s verification?

98.9% accurate — based on live SMTP checks, DNS validation, and behavioral pattern analysis.

Does HEY use a spam filter?

Not directly. HEY uses a reputation-based inbox scanner that filters out marketing content before it reaches spam filters.

Can I send to HEY users with a high bounce rate?

No. High bounce rates damage sender reputation. Even a 0.5% bounce rate can trigger screening on HEY and other providers.

What’s the best way to maintain good sender reputation?

Clean your list regularly, avoid disposable domains, verify new addresses in real time, and ensure engagement through relevant content.

How can I test if my emails land in HEY inboxes?

Use MailTester’s inbox-placement testing to send to real HEY addresses and confirm delivery success before full campaigns.

Do HEY accounts use different mail servers than Gmail or Outlook?

Yes — HEY operates its own mail infrastructure, including proprietary screening systems that prioritize user privacy and inbox control.