You build a great product, craft a thoughtful message, hit send... and then your user says, “I didn’t get the email.” So you check your logs, everything looks fine, but the message is sitting quietly in their spam folder. Oops, embarrassing!This is one of the most frustrating parts of running an app or sending transactional emails. The good news? It’s almost always fixable once you understand what’s going wrong.Let’s unpack why emails go to spam and how you can keep yours landing safely in the inbox.<h2>You haven’t set up proper email authentication</h2>This is the number one reason your emails end up in spam.If your domain isn’t authenticated, email providers like Gmail or Outlook can’t confirm the message is really coming from you. So, to protect users, they flag it as suspicious.Set up three essential DNS records:<ul><li><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/spf-sender-policy-framework">SPF</a> – lists the servers allowed to send emails for your domain.</li><li><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dkim-domainkeys-identified-mail">DKIM</a> – adds a digital signature to prove the email wasn’t modified.</li><li><a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dmarc-domain-based-message-authentication-reporting-conformance">DMARC</a> – tells providers what to do when an email fails SPF or DKIM checks.</li></ul>Once you configure these correctly, you’ll see a noticeable improvement in inbox placement. Tools like <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://www.mail-tester.com/">Mail-Tester</a>, <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://mxtoolbox.com/">MXToolbox</a>, or <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://dmarcian.com/">DMARCian</a> can help verify your setup.<h2>Your sending domain or IP has a poor reputation</h2>Every domain and IP has a reputation score that mailbox providers use to decide where your emails go. If too many of your messages get flagged, bounced, or ignored, your reputation drops, and your next emails are more likely to be filtered as spam.Common causes include:<ul><li>Sending large batches too quickly</li><li>Using shared IPs with other senders who spam</li><li>Getting high bounce or complaint rates</li></ul>To fix this:<ul><li>Warm up new domains gradually instead of blasting thousands of emails on day one.</li><li>Use dedicated IPs if you send high volume.</li><li>Keep your bounce rate below 2% and complaint rate below 0.1%.</li></ul>Think of your sender reputation like a credit score. Consistency, trust, and history matter more than speed.<h2>Your email content looks spammy</h2>Spam filters scan the content of your emails before they reach the inbox. Even if your authentication is perfect, your copy and formatting can still trigger a filter.Here’s what to watch out for:<ul><li>Overuse of “FREE,” “LIMITED TIME,” or “CLICK NOW.”</li><li>Too many images with little text.</li><li>Broken HTML or messy inline styles.</li><li>No plain text version of the email.</li><li>Missing unsubscribe link in marketing emails.</li></ul>Keep your design simple and your tone natural. Write like you’re talking to a person, not pitching a crowd. Always include a clear sender name, recognizable address, and valid contact info.Pro tip: Before sending a campaign, run it through a spam-check tool to see how filters interpret your content.<h2>You’re sending from a new or cold domain</h2>If your domain is brand new or has never sent emails before, providers don’t trust it yet. That’s normal.Start slow. Send small batches to verified or internal addresses, build up a positive history, and monitor engagement. This process is known as <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/blog/how-to-warm-up-a-new-domain-for-transactional-emails">domain warming</a>.You can also use a subdomain for your email traffic, like <code>mail.yourdomain.com</code> or <code>notifications.yourdomain.com</code>. This keeps your main domain safe if something goes wrong.Remember, reputation builds over time. The key is steady, consistent sending behavior.<h2>You’re not monitoring your delivery performance</h2>Email deliverability isn’t a one-time setup. It’s something you have to monitor continuously.Keep an eye on:<ul><li>Bounce logs: Which addresses are failing and why.</li><li>Open and click rates: Low engagement signals filters that your emails aren’t wanted.</li><li>Spam complaints: Even a small spike can affect your reputation.</li></ul>Most modern email platforms provide dashboards or webhook logs for this data. Reviewing them weekly helps you spot patterns before they become serious problems.If you’re sending through APIs or services like AutoSend, you can use Email Activity feature to track your delivery rate and fix authentication or content issues fast.<h2>You’re mixing transactional and promotional content</h2>This is an easy mistake to make. Transactional emails are system messages triggered by user actions (signup confirmations, password resets, invoices). Promotional emails are sent to promote something (updates, offers, new features).Mixing them confuses both users and spam filters. For example:<blockquote>“Your password has been reset successfully. Here’s a 30% discount on your next order.”</blockquote>That’s not a transactional email anymore. Keep them separate. Use different templates, sender names, or subdomains for each type.This clarity helps you stay compliant with laws like CAN-SPAM and improves overall inbox placement.<h2>You’re sending without user consent</h2>Even if you have the best infrastructure, sending emails to people who didn’t opt in is a fast track to the spam folder.Always collect consent before sending marketing messages. Use double opt-in where users confirm their subscription. Make it easy to unsubscribe or change preferences at any time.Trust is a long-term deliverability strategy. The fewer complaints you get, the stronger your domain reputation becomes.<h2>Test before you send</h2>Before sending anything to your full list, send test emails to a few different accounts (Gmail, Outlook, Yahoo) and check where they land.If they consistently show up in spam, inspect the headers and test against spam score tools. Small tweaks in authentication, copy, or formatting can often make the difference.<hr>Landing in the spam folder doesn’t mean your emails are doomed. It’s usually a sign that one or two technical or behavioral factors need attention.Start with authentication, check your domain reputation, simplify your content, and watch your logs. Over time, your inbox placement will improve and stay consistent.Good deliverability is not luck. It’s the result of clean setup, good habits, and trust built over time.

You build a great product, craft a thoughtful message, hit send... and then your user says, “I didn’t get the email.” So you check your logs, everything looks fine, but the message is sitting quietly in their spam folder. Oops, embarrassing!This is one of the most frustrating parts of running an app or sending transactional emails. The good news? It’s almost always fixable once you understand what’s going wrong.Let’s unpack why emails go to spam and how you can keep yours landing safely in the inbox.You haven’t set up proper email authenticationThis is the number one reason your emails end up in spam.If your domain isn’t authenticated, email providers like Gmail or Outlook can’t confirm the message is really coming from you. So, to protect users, they flag it as suspicious.Set up three essential DNS records:SPF – lists the servers allowed to send emails for your domain.DKIM – adds a digital signature to prove the email wasn’t modified.DMARC – tells providers what to do when an email fails SPF or DKIM checks.Once you configure these correctly, you’ll see a noticeable improvement in inbox placement. Tools like Mail-Tester, MXToolbox, or DMARCian can help verify your setup.Your sending domain or IP has a poor reputationEvery domain and IP has a reputation score that mailbox providers use to decide where your emails go. If too many of your messages get flagged, bounced, or ignored, your reputation drops, and your next emails are more likely to be filtered as spam.Common causes include:Sending large batches too quicklyUsing shared IPs with other senders who spamGetting high bounce or complaint ratesTo fix this:Warm up new domains gradually instead of blasting thousands of emails on day one.Use dedicated IPs if you send high volume.Keep your bounce rate below 2% and complaint rate below 0.1%.Think of your sender reputation like a credit score. Consistency, trust, and history matter more than speed.Your email content looks spammySpam filters scan the content of your emails before they reach the inbox. Even if your authentication is perfect, your copy and formatting can still trigger a filter.Here’s what to watch out for:Overuse of “FREE,” “LIMITED TIME,” or “CLICK NOW.”Too many images with little text.Broken HTML or messy inline styles.No plain text version of the email.Missing unsubscribe link in marketing emails.Keep your design simple and your tone natural. Write like you’re talking to a person, not pitching a crowd. Always include a clear sender name, recognizable address, and valid contact info.Pro tip: Before sending a campaign, run it through a spam-check tool to see how filters interpret your content.You’re sending from a new or cold domainIf your domain is brand new or has never sent emails before, providers don’t trust it yet. That’s normal.Start slow. Send small batches to verified or internal addresses, build up a positive history, and monitor engagement. This process is known as domain warming.You can also use a subdomain for your email traffic, like mail.yourdomain.com or notifications.yourdomain.com. This keeps your main domain safe if something goes wrong.Remember, reputation builds over time. The key is steady, consistent sending behavior.You’re not monitoring your delivery performanceEmail deliverability isn’t a one-time setup. It’s something you have to monitor continuously.Keep an eye on:Bounce logs: Which addresses are failing and why.Open and click rates: Low engagement signals filters that your emails aren’t wanted.Spam complaints: Even a small spike can affect your reputation.Most modern email platforms provide dashboards or webhook logs for this data. Reviewing them weekly helps you spot patterns before they become serious problems.If you’re sending through APIs or services like AutoSend, you can use Email Activity feature to track your delivery rate and fix authentication or content issues fast.You’re mixing transactional and promotional contentThis is an easy mistake to make. Transactional emails are system messages triggered by user actions (signup confirmations, password resets, invoices). Promotional emails are sent to promote something (updates, offers, new features).Mixing them confuses both users and spam filters. For example:“Your password has been reset successfully. Here’s a 30% discount on your next order.”That’s not a transactional email anymore. Keep them separate. Use different templates, sender names, or subdomains for each type.This clarity helps you stay compliant with laws like CAN-SPAM and improves overall inbox placement.You’re sending without user consentEven if you have the best infrastructure, sending emails to people who didn’t opt in is a fast track to the spam folder.Always collect consent before sending marketing messages. Use double opt-in where users confirm their subscription. Make it easy to unsubscribe or change preferences at any time.Trust is a long-term deliverability strategy. The fewer complaints you get, the stronger your domain reputation becomes.Test before you sendBefore sending anything to your full list, send test emails to a few different accounts (Gmail, Outlook, Yahoo) and check where they land.If they consistently show up in spam, inspect the headers and test against spam score tools. Small tweaks in authentication, copy, or formatting can often make the difference.Landing in the spam folder doesn’t mean your emails are doomed. It’s usually a sign that one or two technical or behavioral factors need attention.Start with authentication, check your domain reputation, simplify your content, and watch your logs. Over time, your inbox placement will improve and stay consistent.Good deliverability is not luck. It’s the result of clean setup, good habits, and trust built over time.

Learn why your emails are going to spam and how to fix it. A simple guide to improve email deliverability, authentication, and sender reputation.

Emails Going to Spam? Here’s How to Fix It

Transactional emails are the quiet workhorses of any product. They confirm signups, reset passwords, send receipts, and quietly keep users connected to what they just did.But here’s the catch. Because they “just work,” most teams stop paying attention to them after setting things up. That’s when small mistakes start slipping in. A missing link. A message stuck in spam folder. Or emails that never arrive.These little things can hurt your product’s trust, conversions, and reputation more than you think.Let’s talk about the five common mistakes people make with transactional emails and how to avoid them.<h2>1. Mixing transactional and marketing emails</h2>This is one of the biggest red flags!Transactional emails are triggered by what the user does, like signing up, verifying their address, or completing a payment. Marketing emails, on the other hand, are sent by you, such as newsletters, offers, or feature updates.When you mix the two, you create confusion and risk deliverability issues. Even a single promotional line can change how email providers treat your message.Example of what not to do:<blockquote>“Your password has been reset successfully. By the way, here’s 20% off your next order.”</blockquote>That’s not transactional anymore. It’s a marketing email disguised as a notification. Email clients (Gmail, Outlook, etc) most probably blacklist your sending domain for doing this!If you send both kinds, separate them properly. Use subdomains like <code>notifications.yourdomain.com</code> for transactional emails and <code>updates.yourdomain.com</code> for marketing. It helps you stay compliant and keeps your sender reputation clean.Tip: We use main (root) domain for certain marketing emails like product updates because they need to come from a builder than a brand. We also encourage users to reply to these emails by asking for feedback or feature requests.<hr><h2>2. Skipping authentication and deliverability setup</h2>Email authentication is not optional. Without it, your messages might never reach inboxes.Set up <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/spf-sender-policy-framework">SPF</a>, <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dkim-domainkeys-identified-mail">DKIM</a>, and <a target="_blank" rel="noopener noreferrer" class="break-all link-break text-gray-500 hover:underline" href="https://autosend.com/glossary/dmarc-domain-based-message-authentication-reporting-conformance">DMARC</a> for your sending domain. These records prove that your emails are legitimate and authorized. Without them, providers like Gmail or Outlook might flag them as suspicious.Think of these as ID checks for your emails. No ID, no entry.It’s good practice to run a deliverability test every few months using tools like Mail-Tester or DMARC checkers. It keeps your transactional emails reliable and builds trust with both users and email providers.<hr><h2>3. Forgetting to handle delivery failures and retries properly</h2>Even the best email infrastructure can fail sometimes. Servers can timeout, domains can throttle requests, or recipients’ mailboxes can temporarily reject messages.If your app isn’t set up to handle retries or log failures, some of your most important messages might never get delivered.Imagine a user waiting for a password reset link that failed to send because of a temporary network issue. They’ll just assume your product is broken.To avoid this, implement a retry mechanism with exponential backoff and store failed events in a queue or log for review. Most modern email APIs provide webhooks or event logs for this exact reason.It’s not enough to “fire and forget.” Always know what happened after you clicked send.<hr><h2>4. Making them hard to read or inaccessible</h2>A lot of transactional emails fail because of how they’re written.People open these emails when they’re trying to complete a specific task such as verifying an account, resetting a password, or viewing a receipt. They’re not in the mood to read long paragraphs.Make it easy.<ul><li>Keep sentences short and direct.</li><li>Use descriptive subject lines like “Confirm your email” or “Your order is confirmed.”</li><li>Place the main action or link at the top.</li><li>Add alt text to images and maintain good contrast for readability.</li></ul>Accessibility is not just a compliance requirement. It’s how you show respect for your users’ time and attention.<hr><h2>5. Not tracking logs or monitoring performance</h2>Transactional emails are often treated as “set it and forget it.”But things break. DNS updates, expired credentials, or throttling by mail servers can stop your messages from reaching users. If you don’t monitor delivery logs, bounce rates, or error messages, you won’t know there’s a problem until users start complaining.Regularly reviewing logs helps you catch issues early. You can also identify trends like delayed deliveries or domain-specific bounce patterns. Treat this like uptime monitoring for your email system.<hr><h2>Bonus: Don’t add an unsubscribe link to transactional emails</h2>This might sound strange, but you should not include an unsubscribe link in your transactional emails.These emails are often critical to account security and compliance. Think password resets, account verifications, billing alerts, or privacy notifications. If users could unsubscribe from these, they might miss important system information that affects their accounts.However, this applies only to genuine transactional emails. If your message includes any promotional content such as product updates, feature highlights, or discounts, it becomes a marketing email, and laws like CAN-SPAM or GDPR require a clear opt-out link.The best rule of thumb is:<ul><li>Keep transactional emails strictly functional.</li><li>Reserve unsubscribe links for marketing or promotional messages.</li></ul>That balance keeps you compliant while ensuring essential messages always reach your users.<hr>Transactional emails might look simple, but they carry real weight. They’re often the most opened messages your users will ever receive.Avoid these five mistakes: mixing content types, skipping authentication, not handling delivery failures, writing unclear copy, and neglecting logs. And remember, not every email needs an unsubscribe link.When your transactional emails are fast, clear, and consistent, they quietly strengthen your brand every single day.

Transactional emails are the quiet workhorses of any product. They confirm signups, reset passwords, send receipts, and quietly keep users connected to what they just did.But here’s the catch. Because they “just work,” most teams stop paying attention to them after setting things up. That’s when small mistakes start slipping in. A missing link. A message stuck in spam folder. Or emails that never arrive.These little things can hurt your product’s trust, conversions, and reputation more than you think.Let’s talk about the five common mistakes people make with transactional emails and how to avoid them.1. Mixing transactional and marketing emailsThis is one of the biggest red flags!Transactional emails are triggered by what the user does, like signing up, verifying their address, or completing a payment. Marketing emails, on the other hand, are sent by you, such as newsletters, offers, or feature updates.When you mix the two, you create confusion and risk deliverability issues. Even a single promotional line can change how email providers treat your message.Example of what not to do:“Your password has been reset successfully. By the way, here’s 20% off your next order.”That’s not transactional anymore. It’s a marketing email disguised as a notification. Email clients (Gmail, Outlook, etc) most probably blacklist your sending domain for doing this!If you send both kinds, separate them properly. Use subdomains like notifications.yourdomain.com for transactional emails and updates.yourdomain.com for marketing. It helps you stay compliant and keeps your sender reputation clean.Tip: We use main (root) domain for certain marketing emails like product updates because they need to come from a builder than a brand. We also encourage users to reply to these emails by asking for feedback or feature requests.2. Skipping authentication and deliverability setupEmail authentication is not optional. Without it, your messages might never reach inboxes.Set up SPF, DKIM, and DMARC for your sending domain. These records prove that your emails are legitimate and authorized. Without them, providers like Gmail or Outlook might flag them as suspicious.Think of these as ID checks for your emails. No ID, no entry.It’s good practice to run a deliverability test every few months using tools like Mail-Tester or DMARC checkers. It keeps your transactional emails reliable and builds trust with both users and email providers.3. Forgetting to handle delivery failures and retries properlyEven the best email infrastructure can fail sometimes. Servers can timeout, domains can throttle requests, or recipients’ mailboxes can temporarily reject messages.If your app isn’t set up to handle retries or log failures, some of your most important messages might never get delivered.Imagine a user waiting for a password reset link that failed to send because of a temporary network issue. They’ll just assume your product is broken.To avoid this, implement a retry mechanism with exponential backoff and store failed events in a queue or log for review. Most modern email APIs provide webhooks or event logs for this exact reason.It’s not enough to “fire and forget.” Always know what happened after you clicked send.4. Making them hard to read or inaccessibleA lot of transactional emails fail because of how they’re written.People open these emails when they’re trying to complete a specific task such as verifying an account, resetting a password, or viewing a receipt. They’re not in the mood to read long paragraphs.Make it easy.Keep sentences short and direct.Use descriptive subject lines like “Confirm your email” or “Your order is confirmed.”Place the main action or link at the top.Add alt text to images and maintain good contrast for readability.Accessibility is not just a compliance requirement. It’s how you show respect for your users’ time and attention.5. Not tracking logs or monitoring performanceTransactional emails are often treated as “set it and forget it.”But things break. DNS updates, expired credentials, or throttling by mail servers can stop your messages from reaching users. If you don’t monitor delivery logs, bounce rates, or error messages, you won’t know there’s a problem until users start complaining.Regularly reviewing logs helps you catch issues early. You can also identify trends like delayed deliveries or domain-specific bounce patterns. Treat this like uptime monitoring for your email system.Bonus: Don’t add an unsubscribe link to transactional emailsThis might sound strange, but you should not include an unsubscribe link in your transactional emails.These emails are often critical to account security and compliance. Think password resets, account verifications, billing alerts, or privacy notifications. If users could unsubscribe from these, they might miss important system information that affects their accounts.However, this applies only to genuine transactional emails. If your message includes any promotional content such as product updates, feature highlights, or discounts, it becomes a marketing email, and laws like CAN-SPAM or GDPR require a clear opt-out link.The best rule of thumb is:Keep transactional emails strictly functional.Reserve unsubscribe links for marketing or promotional messages.That balance keeps you compliant while ensuring essential messages always reach your users.Transactional emails might look simple, but they carry real weight. They’re often the most opened messages your users will ever receive.Avoid these five mistakes: mixing content types, skipping authentication, not handling delivery failures, writing unclear copy, and neglecting logs. And remember, not every email needs an unsubscribe link.When your transactional emails are fast, clear, and consistent, they quietly strengthen your brand every single day.

The email blog

Stories, strategies, and insights for sending better emails.