Why are my Klaviyo preview emails not showing up in my inbox?
Michael Ko
Co-founder & CEO, Suped
Published 11 Aug 2025
Updated 17 Aug 2025
7 min read
It can be incredibly frustrating when you send a preview email from Klaviyo and it simply doesn't show up in your inbox. You've checked the spam folder, the promotions tab, and even searched your entire mailbox, but there's no trace of it. This is a common issue many email marketers face, and it often points to underlying deliverability challenges that extend beyond just preview sends.
Unlike live email campaigns, preview emails can sometimes be subjected to different, and often stricter, filtering mechanisms. These can be imposed by your own company's internal network security, specific mailbox provider (MBP) policies for test messages, or even the way Klaviyo sends test emails versus live campaigns.
This guide explores the primary reasons why your Klaviyo preview emails might not be reaching their intended destination and provides actionable steps to diagnose and resolve these issues. We'll cover everything from email authentication and sender reputation to corporate network filters and how mailbox providers handle test sends.
Common causes: authentication, content, and reputation
Email authentication, including SPF, DKIM, and DMARC, forms the backbone of email deliverability. Even for preview emails, proper authentication is crucial. If your domain's authentication records are not correctly set up, mailbox providers may view your emails with suspicion, leading them to be blocked or sent directly to the spam folder, regardless of whether it's a test or a live send. A common issue is a misconfigured DMARC record or a poor sender reputation (for your domain or the sending IP), which can severely impact delivery to all inboxes.
Authentication issues
Missing DNS records: Incomplete or incorrect SPF, DKIM, or DMARC records prevent proper verification of your emails, causing them to be flagged as suspicious.
DMARC policy: If your DMARC policy is set to quarantine (`p=quarantine`) or reject (`p=reject`), emails failing authentication will be moved to spam or blocked entirely. Even for previews, this can occur.
Domain reputation: A low domain reputation, perhaps from previous issues, can cause all your sends, including tests, to be filtered.
Beyond technical authentication, the content of your email plays a significant role. Even if it's a preview, spam filters analyze text, links, and images. Using too many spammy keywords, broken links, or suspicious formatting can trigger filters and prevent your email from reaching the inbox. This is why it is so important to perform proper email deliverability tests before sending campaigns.
If you're sending preview emails to an address within your corporate network, internal firewalls or email security solutions can be a major culprit. Companies often employ advanced security systems, such as Proofpoint or similar gateway filters, that are designed to block suspicious or unauthenticated emails before they even reach your inbox. These systems might flag emails coming from marketing automation platforms, even legitimate ones, as potential threats or spam.
Internal network and mailbox provider filtering
Mailbox providers also handle test emails in their own ways. For example, Gmail might automatically categorize test emails, especially if they resemble promotional content, into the Promotions tab. Similarly, Outlook (and Microsoft 365 mailboxes) may apply stricter spam filters to incoming emails, including test sends, particularly if they originate from marketing platforms that are frequently targeted by spammers. This can lead to your emails being placed in the junk folder, or blocked entirely, as discussed in this guide on test emails in junk.
Typical filtering for live campaigns
Live campaigns are generally optimized for bulk sending and are judged based on overall sender reputation, content relevance, and engagement metrics from a large audience. Mailbox providers assess your historical sending behavior.
Unique filtering for preview emails
Preview emails, especially those sent to internal addresses, can be subject to corporate firewalls that may block unknown senders or marketing platforms. They lack the positive engagement signals of a broad list, making them more susceptible to filters.
Furthermore, if you are sending multiple identical test emails in a short period, some mailbox providers might interpret this as unusual activity, akin to a spam run, and temporarily block or throttle your incoming messages. This behavior is designed to protect users from unsolicited bulk email, even if your intentions are benign.
Klaviyo's preview environment and testing considerations
It's important to distinguish between Klaviyo's internal preview function and sending a test email to an inbox. The former is an in-platform rendering, while the latter is an actual email send that goes through Klaviyo's sending infrastructure and then through the recipient's mailbox provider. Only actual test emails will encounter the filtering mechanisms discussed earlier.
Klaviyo's sending IPs, while generally well-maintained, are shared among many users. If other Klaviyo users on the same shared IP have engaged in poor sending practices, it could temporarily affect the IP's reputation, potentially impacting your preview emails. This is a deliverability challenge that can occur even with reputable email service providers (ESPs).
Another factor is how dynamic content and personalization variables render in test emails. Sometimes, merge tags may not fully resolve in preview emails, which can lead to broken content or display issues that might be misinterpreted by spam filters. Always ensure your test email looks as expected, especially if it relies heavily on personalized data.
Practical steps to troubleshoot missing previews
When your Klaviyo preview email doesn't appear, the first and most crucial step is to perform a thorough check of all possible inbox locations. Many times, emails end up in folders other than the primary inbox without explicit notification. Check your spam or junk folder, the promotions tab (for Gmail users), and any other categorized folders in your inbox. Use the search function within your email client, too.
If the email is still nowhere to be found, try sending the preview to multiple different email addresses from various mailbox providers (e.g., a personal Gmail, an Outlook.com address, and your corporate email). This helps identify if the issue is specific to one recipient address or a broader problem. You can also use online email testing tools like About My Email to get a detailed report on deliverability and potential issues.
If the problem persists across different recipients, it's time to dig into the technical details. Verify your domain's SPF, DKIM, and DMARC records are correctly configured and aligned. If you suspect your domain or IP might be on a blacklist or blocklist, a blocklist monitoring service can provide insights. Finally, if all else fails, reach out to Klaviyo support with as much detail as possible, including recipient email addresses and timestamps of your test sends. They can often provide server-side logs to diagnose delivery failures.
Spammy keywords, broken links, or suspicious formatting.
Review content against spam filter guidelines, use text-only previews.
Klaviyo specifics
Shared IP issues, dynamic content rendering problems.
Contact Klaviyo support for server-side logs.
Views from the trenches
Best practices
Always check all email folders including spam, promotions, and junk before assuming non-delivery.
Use a variety of recipient email addresses (e.g., Gmail, Outlook, Yahoo) for testing to identify isolated issues.
Verify your email authentication records (SPF, DKIM, DMARC) are correctly set up and passing.
Communicate with your IT department to ensure internal firewalls are not blocking test emails from Klaviyo.
Send test emails from Klaviyo to dedicated testing tools to get detailed deliverability reports.
Common pitfalls
Assuming an email isn't delivered without thoroughly checking all possible inbox folders.
Overlooking corporate firewalls or email security solutions as a cause for blocked test emails.
Not regularly checking your domain's authentication records and sender reputation.
Sending too many identical test emails in a short period, which can trigger spam filters.
Failing to differentiate between Klaviyo's in-platform preview and an actual test email send.
Expert tips
Ensure the domain you are sending from has a proper DMARC policy in place to ensure deliverability.
If preview emails aren't arriving, check if your company's email security (like Proofpoint) is blocking them.
When troubleshooting, test with multiple email addresses across different providers to isolate the issue.
Verify that Klaviyo's sending domain is correctly whitelisted by any internal network firewalls.
Look into any error messages Klaviyo provides when sending test emails, they often give clues.
Expert view
Expert from Email Geeks says that none of the common failures should prevent test email delivery. It would be advisable to ask Klaviyo for assistance to see if the ISP receiving the tests is blocking your Klaviyo sending IP or domain.
2024-04-05 - Email Geeks
Marketer view
Marketer from Email Geeks says that if your company uses Proofpoint or similar firewall technology, it is likely preventing test emails from coming through. You may need to collaborate with your IT team to whitelist Klaviyo as an approved sender within Proofpoint or similar systems.
2024-04-05 - Email Geeks
Ensuring your test emails arrive
Resolving missing Klaviyo preview emails often involves a combination of careful troubleshooting and understanding various factors that influence email deliverability. From ensuring proper email authentication and maintaining a healthy sender reputation to navigating internal network filters and specific mailbox provider behaviors, each element plays a critical role.
By systematically checking all potential causes and utilizing the right tools, you can identify why your previews aren't arriving and take corrective action. This proactive approach not only solves the immediate problem of missing test emails but also contributes to overall improved email deliverability for your live campaigns, ensuring your messages consistently reach your audience's inboxes.
Gmail might automatically categorize test emails, especially if they resemble promotional content, into the Promotions tab. Similarly, 
Outlook (and 
Microsoft 365 mailboxes) may apply stricter spam filters to incoming emails, including test sends, particularly if they originate from marketing platforms that are frequently targeted by spammers. This can lead to your emails being placed in the junk folder, or blocked entirely, as discussed in this guide on test emails in junk.
