Why are My Sign-Up Verification Emails Going to Spam?

Zack Aab

4 minute read

It’s every email marketer’s worst nightmare: despite all your hard work, your emails are landing in the spam folder. This problem is particularly painful when you’re trying to send simple confirmation emails to your users. Although spam folders serve an important purpose, they can wreak havoc for honest email marketers. If you’re landing in the spam folder, don’t worry. The reality is that everyone faces deliverability problems at some point.

Your spam folder woes could be due to three potential culprits. Thankfully, this incredibly common problem has many easy remedies.

Problem #1: Authentication


DKIM (DomainKeys Identified Mail) is an authentication method that proves the identity of the DKIM domain. It also proves whether or not an email was intercepted and tampered with in transmission. Spammers have been known to intercept important transactional emails. During the interception, they replace the content with their spam message. Spammers then resend the email in the hopes that it will be delivered as if it’s from the original sender.

DKIM prevents this abusive tactic from working. That’s why major email providers examine transactional or confirmation emails without DKIM with suspicion. However, this suspicion potentially aggravates a small issue into a major one.

In fact, Inbox Pros encountered a surprising number of triggered and confirmation emails that do not use DKIM. Email marketers often don’t use DKIM because the email program was set up in a rush or simply because their service provider did not offer it. The result is spammer vulnerability and decreased deliverability.


In order to protect their users and provide a good experience, ISPs and filters look closely at identities. It’s important to understand that the “From” domain is not directly proven, so filters check to see if either the DKIM or SPF domain is the same. This is called alignment. Even though you’ve fully authenticated your promotional emails, you might use a different IP, domain, or service provider for triggered confirmation emails. If you typically send trusted emails from your own domain for DKIM or SPF, an inconsistent IP, domain, or service provider looks suspicious. Email clients can see the email is from you, but with different DKIM and SPF identities, they send you to the spam folder out of caution.

It isn’t a deal-breaker to be out of alignment. However, if everything else you send does have alignment, a one-off batch of non-aligned emails looks sketchy.

The problem amplifies if you’re protecting your domain with DMARC. DMARC, or Domain-based Message Authentication, Reporting and Conformance, authenticates your emails. DMARC has standardized protocols that link your domain name to SPF and DKIM. Many senders implement DMARC to protect their domains from email fraud.

The problem is that senders can accidentally forget about a tool that quietly sent emails without SPF or DKIM alignment.

Problem #2: Content

HTML and Plain Text

Another common spammer tactic is to disguise spam messages as correspondence emails. This has caused email providers to scrutinize plain-text emails from bulk email services. To get around this problem, use a clean and simple HTML email template. Create a complementary and matching plain text version. This renders your email correctly even if your user is behind a strict no-HTML filter. If you’re a B2B sender, this will fix many of your spam folder woes.

Don’t forget to manually check the plain text version for CAN-SPAM compliance and readability. Many “automatic” plain text versions generated from the HTML by the sender’s provider come out very poorly—and sometimes they’re even non-compliant!

Keywords and Design

Spammers aside, filters and ISPs are on the lookout for emails that provide a poor user experience. When in doubt about your design, keep it simple. Avoid large images or huge templates for your confirmation emails. Keyword filtering is no longer a major part of deliverability for ISPs, so most marketers simply need to follow simple best practices. Target your users with relevant content to avoid keyword filtering.

However, keywords are still used by filters and mailbox providers to tell the difference between promotional and transactional messages. All providers want to deliver transactional messages to their users, even if they might frown upon your marketing strategies.

Therefore it’s very important that your confirmation emails look like confirmation emails: no promotional content, no affiliate links, and no conversion CTAs.

Remember that confirmation emails should never do more than these three things:

  1. Confirm the opt-in
  2. Offer an opt-out
  3. Set expectations about email frequency

Reason #3: Reputation

Domains and IPs

Reputation is an important part of email deliverability. Reputation refers to the aggregated history of user behavior, as well as other attributes that a receiver can track in your emails.

Your reputation includes:

  • From domain
  • DKIM and SPF domains
  • Source IP
  • Domains in the content itself
  • HTML templates and patterns

All of these histories come into play when the system decides where to place emails. This means that, if the only relation to your brand in the confirmation email is the From domain, you’re at the mercy of other senders who use the same sending tool.

Take advantage of your good reputation. Use DKIM or SPF domains, as well as link redirects and content, instead of just using the brand name in your From address.

User Expectations

Marketers have to set user expectations from the very first opt-in. First of all, the user should be expecting your confirmation email. Although the filter can’t read the user’s mind, if the user is expecting a confirmation and doesn’t receive one, they are much more likely to look for it in their spam folder. A user clicking “This is not spam” is the fastest way to get out of the spam folder for any major mailbox provider. But that’s not likely to happen if the user doesn’t expect your email. This means you need to review your opt-in process to set expectations at every step. Expectation management also helps users know when to expect emails from you.

Need more help? Call the Email Deliverability Experts

Still facing deliverability problems? Don’t worry! Trendline is your go-to for email deliverability solutions. To see more subscriber emails in the inbox and a bigger ROI from your email marketing efforts. Give us a ring.

Trendline Interactive

Ready to send better messages?

About the Author(s)

Zack Aab

Before learning how to use email, Zack worked in computer repair, blacksmithing, video production, and knot-tying, but not all at once. Zack has his CIPP/US certification, is definitely not a lizard person, and likes normal human things like email and data privacy and basking on sunny rocks. Follow Zack on LinkedIn

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