Why your emails land in spam—and how to fix it

You can write the perfect cold email — an email so compelling you could sell sand in the desert.

But if you can't get that email into your prospects' inboxes, it will go unseen and unread, lost to the digital abyss that is the spam folder. For B2B sales teams scaling their outreach, deliverability isn't just another metric — it's the foundation of your pipeline.

Apollo.io breaks down why your emails land in spam and, more importantly, how to fix it. We'll cover the technical setup, domain strategies, and ongoing practices that separate top performers from everyone else stuck in spam folders.

What is email deliverability and why does it matter for sales?

Email deliverability is simple: It's your ability to land an email in someone's main inbox instead of their spam folder. It's not the same as email delivery, which just confirms an email was sent. Deliverability is about where it ends up.

For sales teams, deliverability is crucial. A perfect email that lands in spam is a wasted effort. Strong deliverability means more prospects see your message, which leads to more conversations, more meetings booked, and ultimately, more revenue. It's the foundation of any successful outbound strategy.

How not to sound like a scammer, spammer, or spoofer

You're probably sending a lot of outbound emails every day, but do you understand the mechanisms behind email sending?

Benny Rubin, CEO and Founder at Senders, recently shared the three key components of cold outbound.

• Sendability: How many emails can I send?
• Deliverability: Will my emails reach my prospects' inboxes?
• Efficacy: Can I conduct email outreach in a way that doesn't waste resources?

If you don't pay attention to these factors, especially deliverability, your emails will likely end up in spam. Benny saw this happen firsthand.

He was running a high volume of cold outbound sequences and needed to scale quickly. He started by creating multiple inboxes to evade Google Workspace limits. While this solved his sendability problems, it created deliverability issues, and most of his emails ended up in spam.

"I realized I was missing something very, very fundamental in my desire to evade restrictions placed on my sending. I had stopped acting like a legitimate business sender and started acting like a spammer, spoofer, or scammer," shares Benny.

So, what can you do to make sure you don't look like a spammer, spoofer, or scammer? Keep reading to find out.

Why your emails are landing in spam (and how to fix it)

So, what are the usual suspects that send your emails to the spam folder? It usually comes down to a few key areas: your domain's reputation, your technical setup, your sending behavior, and your email's content. Getting any of these wrong can hurt your ability to reach the inbox. Let's break down how to get each one right.

Carefully select your domains

If your domain isn't set up properly, you risk getting sent to the spam folder.

Using new domains can make you look like a spammer. You should use domains that are 30 days or older. The longer you hold a domain, the more credible it looks. Think about your credit score. When you opened your first credit card, your score was probably pretty low. Then, once you built up credit over time, your score likely increased, making you look more legitimate. An email domain is no different.

Another way to look like a spammer? Spelling mistakes. When creating new domains, choose ones that are similar to your primary domain and make sure you avoid spelling errors. For example, "bankofamericas" looks a little fishy, don't you think? The content in your email should also match the domain. If you're sending an email from Bank of America, the body of the email should contain relevant banking and financial information.

Lastly, consider using subdomains. Subdomains take on the age of the original domain and are an efficient way to add more domains, without spending more money.

“Not having proper domain authentication is like going to the border without a passport.”

- Benny Rubin, CEO and Founder at Senders

Set up authentication

SPF, DKIM, and DMARC are email ID systems. They are forms of domain authentication and are coded into the backend of wherever you host your domain records.

When you send an email, the email server looks at where the email came from and searches for reasons to reject the email (misspelled domain, new domain, redirect links in the email copy, etc.). Then, they ask the sending email server if anything looks off. If you don't supply your ID, your email likely isn't ending up in your recipient's inbox.

Apollo.io

Respect the rules of the sender platform

One of the number one rules of outbound?

"Don't abuse the infrastructure," says Benny.

Regardless of where you send from (Google, Outlook, Sendgrid, etc.), you need to make sure you don't violate the rules of the sender platform.

To avoid appearing as a spammer, spoofer, or scammer, familiarize yourself with the relevant acceptable use policies.

For example, consider how many emails you are sending, and how often. If Google sees a sudden increase in email sends, they may flag you as a spammer. Be mindful of relevant guidelines and your deliverability will improve.

Consider your email copy

When it comes to reaching peak deliverability, it matters what's included within the email body, too.

When crafting outbound emails, it's okay to include links, but use only direct links. Redirects, links to Google Drive, or too many links, can look spammy. You also want to avoid spam red flags like using all capital letters or symbols. Keep your emails engaging, but professional.

Lastly, email signatures are a great way to show your credibility. Including details like your full name, title, and company adds a level of legitimacy because this is exactly the kind of information that spammers don't want to include.

Warm up your email domains the right way

You can't take a brand new domain and start sending hundreds of emails a day. That's a huge red flag for email providers. Instead, you need to warm it up.

Think of it like building credit. You have to make small, consistent efforts over time to prove you're trustworthy. Start by sending a low volume of emails (10-20 per day) to highly engaged contacts or colleagues. Gradually increase your sending volume each day over several weeks. This slow ramp-up shows providers that you're a legitimate sender, not a spammer.

Monitor and measure your email deliverability

You can't fix what you can't see. Keep a close eye on your email metrics to catch problems early. The most important metric is your bounce rate — if it's high, your deliverability is low. Also, watch your open rates and spam complaint rates. A sudden drop in opens or a spike in complaints is a clear sign that you're having trouble reaching the inbox. Platforms like Apollo provide analytics that make it easy to track these signals and diagnose any issues with your sequences.

Start landing in inboxes consistently

Getting deliverability right isn't a one-time fix; it's an ongoing practice. By focusing on your domain health, technical setup, and sending habits, you build a strong foundation for outreach that gets seen. If you're still running into trouble, here are a few final tips:

• Stop using a damaged domain immediately. Put it in artificial warming until it's healthy.
• Rotate in a warmed domain that is aged 30+ days.
• Scale up sends slowly (25 emails a day), and send the emails to receptive audiences.
• Confirm you are only emailing verified leads. Data cleaning and enriching is a good way to ensure your email list is ready to go.

Now that you know why emails end up in spam and how to fix it, you can turn your attention to what matters most: starting conversations.

Frequently asked questions about email deliverability

What's a good deliverability rate for email?

You should aim for a deliverability rate of 98% or higher, which means your bounce rate is 2% or less. Anything below 95% is a sign that you need to investigate potential issues with your domain, list quality, or content.

How do you measure email deliverability?

The most direct way is by tracking your bounce rate. A low bounce rate indicates high deliverability. You can also use open rates and spam complaint rates as secondary indicators to monitor the health of your outreach.

How long does it take to warm up a new email domain?

A proper warmup typically takes two to four weeks. The key is to increase your sending volume gradually and consistently during this period to build a positive reputation with email providers.

What happens if my domain gets blacklisted?

If your domain is on a blacklist, your emails will be blocked by servers that use that list. You'll need to identify why you were listed, fix the underlying problem (like a high bounce rate or spam complaints), and then follow the specific blacklist's process to request removal.

Should I use a separate domain for cold outreach?

Yes, it's a highly recommended best practice. Using a secondary domain for cold outreach protects your primary corporate domain's reputation, ensuring that your critical business emails (like those to customers or investors) are never affected by your outbound sales activities.

This story was produced by Apollo.io and reviewed and distributed by Stacker.