Why are my Klaviyo preview emails not showing up in my inbox?

Key findings

• Undelivered previews: A Klaviyo preview email not appearing in the inbox, promotions tab, or spam folder suggests a more severe delivery blockage rather than simple filtering.
• ISP or MBP blocking: The recipient's Internet Service Provider (ISP) or Mailbox Provider (MBP) might be blocking the test email, potentially due to issues with Klaviyo's sending IP or your domain's reputation. This is a common reason why emails might not appear despite successful delivery reports.
• Firewall interference: Corporate firewalls, such as Proofpoint, can prevent test emails from reaching internal inboxes. These systems are designed to filter out suspicious or unapproved senders.
• Authentication status: Although test emails are typically less scrutinized, fundamental authentication issues (like misconfigured SPF, DKIM, or DMARC records) can still impede delivery, even for preview messages. Ensuring proper email authentication is crucial for all email sending.

Key considerations

• Verify klaviyo sending: Confirm with Klaviyo support that the test emails are indeed being sent from their end and not encountering an internal platform error. Reviewing Klaviyo's guide on how to preview and send test emails can help rule out user error.
• Test with alternative addresses: Send preview emails to various destination addresses (e.g., Gmail, Outlook, Yahoo) to determine if the issue is specific to a particular ISP or mailbox provider. This can help narrow down the cause of the non-delivery.
• Check email firewall settings: If your organization uses an email security gateway or firewall, work with your IT team to whitelist Klaviyo as an approved sender. This ensures that internal systems do not inadvertently block legitimate test emails.
• Monitor deliverability: Regularly monitor your email deliverability and sender reputation. While preview emails are tests, persistent issues can signal broader problems that affect your regular campaigns, such as why your emails are going to spam.

Key opinions

• Complete absence: Marketers frequently report that preview emails are entirely missing, not even landing in spam or promotions folders, indicating a deeper delivery block.
• Klaviyo platform concerns: Some marketers question if the issue lies within Klaviyo's platform or its integration with their specific email setup.
• ISP/MBP blocking: A common sentiment is that the recipient’s email provider (ISP/MBP) might be blocking the test email, often without explicit notification.
• Firewall impact: Corporate email security systems and firewalls (such as Proofpoint) are often cited as culprits that silently intercept test emails.

Key considerations

• Exhaust all folders: Always double-check every folder, including spam, junk, and promotions, before concluding that an email is completely missing. Sometimes, emails might just land in unexpected tabs.
• Test different recipients: Send test emails to a range of personal and corporate email addresses, across different providers (Gmail, Outlook, Yahoo, etc.), to isolate if the issue is recipient-specific.
• Consult klaviyo support: If test emails consistently fail to arrive, escalate the issue to Klaviyo support. They can check logs on their end to see if the emails were successfully handed off or if any errors occurred during sending.
• Review email content: While less common for preview emails, certain content (e.g., specific keywords, excessive links) might trigger spam filters, even for tests. Refer to Klaviyo's guide on preview emails going to spam for more insights.
• Consider domain reputation: A poor sender reputation can affect all emails, including tests. Address underlying deliverability issues to improve overall inbox placement for both campaigns and previews. You can read more about understanding your email domain reputation.

Key opinions

• ISP/MBP blocking is common: Experts frequently point to recipient Internet Service Providers or Mailbox Providers as the primary reason for completely missing test emails, suggesting they may be blocking Klaviyo's sending IP or the sender's domain.
• Firewall interference: Many experts identify corporate firewalls and email security solutions (e.g., Proofpoint) as a significant cause for test emails not appearing, as these systems often block unwhitelisted senders.
• Authentication health: While authentication failures might not always prevent delivery of a single test, experts stress that underlying issues with SPF, DKIM, or DMARC can contribute to general deliverability problems, affecting even previews.
• Test email limitations: Experts note that some failures reported in test environments (e.g., List-ID header issues) might not be critical enough to prevent delivery but could indicate minor configuration issues.
• Proactive testing: Using dedicated email testing services (like Mailgun's inspect emails feature) or external test addresses can provide diagnostic insights that a regular inbox won't.

Key considerations

• Engage klaviyo support: If standard troubleshooting fails, experts recommend contacting Klaviyo directly. They have access to detailed sending logs that can reveal why specific test emails aren't being delivered.
• Use diagnostic tools: Utilize services that provide test addresses and deliverability reports to get granular insights into potential failures. This helps diagnose issues like authentication problems or content-based filtering.
• Whitelist senders: For internal testing, ensure Klaviyo's sending domains and IPs are whitelisted in your company's email security systems to bypass strict internal filters. This helps prevent test emails from being blackholed by firewalls.
• Review DMARC reports: Even for test emails, DMARC reports can offer valuable insights into how your domain is perceived. While test emails might not always generate full reports, reviewing overall domain health is essential. You can gain understanding into understanding DMARC reports.

Key findings

• Preview email intent: Klaviyo documentation explains that preview emails are designed to show how an email will appear in a recipient’s inbox, but they are still sent through the same mail infrastructure as live campaigns.
• Spam folder placement: Official guides acknowledge that preview emails, like regular emails, can sometimes end up in the spam folder due to various factors, including content or sender reputation.
• Firewall and security settings: Documentation often mentions that corporate firewalls or email security software can block emails, requiring specific whitelisting of Klaviyo's sending IPs or domains.
• HTML rendering discrepancies: Different inboxes interpret HTML uniquely, which can lead to display discrepancies, but generally not outright non-delivery for a preview.

Key considerations

• Follow testing procedures: Klaviyo’s documentation details the precise steps for previewing and sending test emails. Adhering to these steps ensures the tests are initiated correctly.
• Check email authentication: Ensure your domain's SPF, DKIM, and DMARC records are correctly configured, as outlined in general deliverability best practices. Even test emails benefit from strong authentication, which can be verified using a free online email testing tool.
• Firewall whitelist: If using a corporate email system, consult the documentation for your email firewall (e.g., Proofpoint) to understand how to whitelist specific senders or domains, allowing Klaviyo test emails to pass through.
• Review suppression lists: Although less likely for preview emails, ensure the test recipient's address is not accidentally on a suppression list within Klaviyo itself, which would prevent any emails from being sent to it. Learn more about why opted-in customers might not receive emails.