Summary
When Klaviyo test emails fail to deliver to Outlook after a sending domain change, the root causes typically stem from issues related to DNS configuration, email authentication, and the new domain's reputation. Outlook, being a stringent mailbox provider, often flags emails from new domains lacking a sending history or proper authentication. Key problems include the new 'From' header domain not existing in DNS, incorrect or unpropagated SPF, DKIM, and DMARC records, and the new domain not being fully verified within Klaviyo. Additionally, delayed DNS propagation, local DNS caching issues, and setting overly strict DMARC policies too early can hinder deliverability. New domains also need a careful warm-up period to build trust with filters, and deliverability can be affected by the reputation of associated shared IP addresses or prior blacklisting.
Key findings
- DNS Misconfiguration: A primary reason for non-delivery is that the 'From:' header domain often does not exist in DNS (lacking MX, A, or AAAA records from the delegated nameservers), which causes mail from unreplyable addresses to be treated poorly by filters.
- Authentication Record Issues: Incorrectly configured, unpropagated, or missing SPF, DKIM, and DMARC records for the new domain are critical. Outlook relies heavily on these authentications to verify email legitimacy, and their absence or errors lead to rejection or junk folder placement.
- Klaviyo Domain Verification: Emails may fail to deliver if the new sending domain has not been fully verified within Klaviyo itself, meaning the platform has not yet recognized and confirmed the updated DNS settings.
- Domain Reputation & Warm-up: New sending domains lack an established reputation with Microsoft's filters. Without prior sending history, Outlook is more cautious and may flag emails as suspicious, making a gradual 'warm-up' period essential.
- DMARC Policy Strictness: A missing or incorrectly configured DMARC record, or setting a strict policy ('p=reject' or 'p=quarantine') too early for a new domain, can lead to immediate rejection by Outlook, especially if any authentication alignment issues are present.
- Delayed DNS Propagation: DNS changes, including those for SPF, DKIM, and DMARC, can take up to 48 hours to propagate across the internet, during which time deliverability to stricter inboxes like Outlook can be negatively impacted.
- Local DNS Caches: Even after global DNS propagation, local DNS caches on recipient mail servers (like Outlook's) might hold onto old DNS records longer than expected, causing temporary delivery failures.
Key considerations
- Initial Troubleshooting: Begin by checking Klaviyo logs for specific error messages and performing a Message Trace in Microsoft Defender, as these steps can often pinpoint the exact reason for non-delivery or blockages from Microsoft.
- Verify DNS Records: Crucially, ensure that SPF, DKIM, and DMARC records for the new sending domain are correctly published and have fully propagated globally. Use online DNS lookup tools like MXToolbox to confirm their status and validity. Also, ensure the Header From domain actually exists in DNS with appropriate A, AAAA, or MX records.
- Allow DNS Propagation Time: Be patient, as DNS record propagation can take up to 48 hours. Even after global propagation, recipient mail servers, including Outlook's, may hold onto old DNS records in their local caches, causing temporary failures.
- Warm-up New Domain: Implement a warm-up strategy for the new sending domain. Sending too many emails too quickly from a domain without prior sending history can trigger spam filters, particularly those of strict ISPs like Outlook, which may flag it as suspicious activity.
- DMARC Policy Strategy: Exercise caution with DMARC policies for new domains. Avoid setting 'p=reject' or 'p=quarantine' initially, as this can lead to emails being outright blocked by Outlook if any SPF or DKIM alignment issues exist. Start with 'p=none' to monitor traffic and ensure proper authentication before enforcing stricter policies.
- Check Klaviyo Settings: Confirm that the correct new sending domain is selected within Klaviyo's email settings for both the overall sending profile and individual email campaigns. Misalignment here can cause deliverability issues.
- Monitor Reputation: Be aware that new domains need to build a positive reputation with Microsoft's filters. Also, check if the new domain or associated shared IP addresses are listed on any blacklists, as this would cause immediate rejection by ISPs like Outlook. Be mindful of shared IP reputation if Klaviyo uses them, as it can temporarily impact a new domain's deliverability.
What email marketers say
9 marketer opinions
Changing a sending domain in Klaviyo often leads to test email delivery issues with Outlook, primarily due to DNS misconfigurations, nascent domain reputation, or incorrect email authentication setups. Outlook, known for its strict filters, scrutinizes new sending domains, making it crucial to ensure all technical prerequisites are met and a proper warm-up strategy is in place.
Key opinions
- Non-existent From Domain: A critical problem is when the 'From' header domain (e.g., e.yourdomain.com) does not have corresponding MX, A, or AAAA records in DNS, making it an unreplyable address, which mail filters often treat as suspicious.
- DMARC Configuration Impact: A missing, incorrectly configured, or overly strict DMARC policy (such as 'p=reject' or 'p=quarantine' set too early) can cause Outlook to reject emails from a new domain, especially if there are any underlying SPF or DKIM alignment issues.
- New Domain Reputation: Without an established sending history, new domains lack reputation, prompting Outlook's spam filters to view emails as potentially suspicious, necessitating a deliberate warm-up period to build trust.
- Shared IP Reputation: If Klaviyo utilizes shared IP addresses, any existing negative reputation associated with those IPs from other senders can temporarily impede deliverability for a new domain, as Outlook is sensitive to IP reputation.
- Blacklisting Concerns: Should the new sending domain or any associated shared IPs have been previously involved in spam activities, they might be blacklisted, leading to immediate email rejection by ISPs like Outlook until delisted.
Key considerations
- Initial Troubleshooting Steps: Start by examining Klaviyo's internal logs for error messages and perform a Message Trace in Microsoft Defender, which can provide specific insights into why emails are being blocked by Microsoft.
- DNS Propagation Time: Allow at least 24-48 hours for DNS changes, including SPF, DKIM, and DMARC records, to fully propagate across the internet, as delayed propagation can temporarily hinder delivery.
- Domain Warm-up Strategy: Implement a gradual warm-up plan for the new domain, increasing sending volume slowly to build a positive reputation with mailbox providers like Outlook and avoid triggering spam filters due to sudden, high-volume activity.
- DMARC Policy Review: For new domains, it is advisable to begin with a DMARC policy of 'p=none' to monitor email authentication and deliverability without risking rejection. Only consider stricter policies after confirming proper SPF and DKIM alignment and stable delivery.
- Klaviyo Sending Domain Alignment: Verify that the newly configured sending domain is correctly selected within Klaviyo's platform settings, specifically for the sending profile and for individual email campaigns, to ensure consistency.
Marketer view
Email marketer from Email Geeks explains that checking Klaviyo logs and performing a Message Trace in Microsoft Defender are good initial troubleshooting steps. He also suggests that Microsoft might be blocking the new domain and reiterates the importance of Message Trace.
6 Oct 2023 - Email Geeks
Marketer view
Email marketer from Email Geeks initially notes that neither the old nor new sending domains had SPF records configured directly, but the apex domain did. After reviewing a test email, he clarifies that the mail was authenticated, but the critical issue was that the From: header domain (e.drgreenlifeorganics.com) did not exist in DNS (lacking MX, A, or AAAA records from the Klaviyo nameservers it was delegated to). He explains that mail from unreplyable addresses is often treated poorly by filters, concluding that this DNS misconfiguration is likely the problem and indicates an issue with the Klaviyo account setup.
19 Oct 2023 - Email Geeks
What the experts say
2 expert opinions
When Klaviyo test emails encounter delivery issues to Outlook following a sending domain change, two primary culprits emerge: the absence of DNS records for the 'Header From' domain itself, and the improper configuration of crucial email authentication protocols. Outlook, as a diligent mailbox provider, heavily relies on these foundational elements to validate email legitimacy, often rejecting or misfiling messages that fail these checks.
Key opinions
- Header From DNS Absence: A significant problem identified is that the 'Header From' domain, which is displayed to recipients, may not have corresponding DNS records, causing emails to fail delivery even if technical authentication like SPF/DKIM for the return path is otherwise sound.
- Authentication Protocol Errors: Improper or missing setup of critical email authentication records, including SPF, DKIM, and DMARC, for the newly changed sending domain is a common reason for non-delivery, as mailbox providers like Outlook use these to verify sender legitimacy.
Key considerations
- Verify Header From DNS: Confirm that the 'Header From' domain (the email address displayed to recipients) has proper DNS records, such as A, AAAA, or MX records, to ensure it is a valid and existing domain, which is crucial for deliverability.
- Complete Authentication Setup: Rigorously ensure that SPF, DKIM, and DMARC records for the new sending domain are correctly configured, published, and have fully propagated. These protocols are indispensable for passing legitimacy checks by mailbox providers like Outlook.
Expert view
Expert from Email Geeks confirms that Klaviyo is not serving any DNS records for the new domain. She clarifies that while email authentication (like SPF/DKIM for the return path) might be technically fine, the core issue is that the Header From domain (e.drgreenlifeorganics.com) does not exist in DNS, which significantly impacts deliverability.
21 Mar 2025 - Email Geeks
Expert view
Expert from Spam Resource explains that when a sending domain is changed, a common reason for test emails not delivering, particularly to mailbox providers like Outlook, is the improper setup of email authentication records (SPF, DKIM, DMARC) for the new domain. Mailbox providers rely on these authentications to verify the legitimacy of emails, and without them, messages are likely to be rejected, sent to the junk folder, or simply not delivered.
17 Jan 2023 - Spam Resource
What the documentation says
5 technical articles
When Klaviyo test emails fail to reach Outlook after a sending domain change, the issues frequently involve more than just a single setting. Ensuring correct and fully propagated DNS records for authentication, confirming the domain's complete verification within Klaviyo, and patiently building a positive reputation with Microsoft's filters are all critical steps. Delays in DNS propagation and local cache refreshes on recipient servers can also temporarily impede delivery, underscoring the layered nature of email deliverability for new domain configurations.
Key findings
- DNS Authentication Errors: Incorrect or unpropagated DNS records, specifically SPF, DKIM, and DMARC, are primary reasons for emails not delivering, as these are crucial for email authentication and are heavily relied upon by Outlook.
- Klaviyo Domain Verification Status: A new sending domain that has not been fully verified within Klaviyo can prevent emails from delivering, as the platform needs to recognize and confirm these settings.
- New Domain Reputation Building: New sending domains need to establish a positive reputation with Microsoft's filters; without an established sending history, Outlook is more cautious and may flag emails from such domains as suspicious.
- Delayed DNS Propagation: DNS changes, including authentication records, can take up to 48 hours to propagate globally, impacting deliverability to stricter inboxes like Outlook during this period.
- Local DNS Cache Issues: Even after global DNS updates, local DNS caches on recipient mail servers, such as Outlook's, can retain old DNS records longer than expected, leading to temporary delivery failures for test emails.
- Importance of Verification Tools: Online tools are crucial to confirm that SPF, DKIM, and DMARC records are correctly published and globally propagated. Errors or delays reported by these tools indicate that mail servers, including Outlook, will likely reject emails.
Key considerations
- Verify All DNS Records: Ensure that SPF, DKIM, and DMARC records for the new sending domain are correctly configured, published, and have fully propagated. Use online DNS lookup tools, such as MXToolbox, to confirm their global status and validity.
- Complete Klaviyo Domain Verification: Confirm that the new sending domain has been fully verified and recognized within your Klaviyo account, as unverified domains will lead to deliverability issues.
- Allow for DNS Propagation Time: Be patient, as DNS record changes, especially for authentication, can take up to 48 hours to fully propagate across the internet, during which time deliverability may be inconsistent.
- Understand New Domain Reputation: Recognize that a new sending domain starts with no reputation, requiring time to build trust with strict mailbox providers like Outlook. Initial caution from their filters is normal.
- Account for Local DNS Caching: Be aware that recipient mail servers, including Outlook's, may hold onto old DNS records in their local caches for longer than global propagation, causing temporary delivery failures until these caches refresh.
Technical article
Documentation from Klaviyo Help Center explains that incorrect or unpropagated DNS records, specifically SPF, DKIM, and DMARC, are primary reasons for emails not delivering after a sending domain change. It emphasizes that these records are crucial for email authentication and can take up to 48 hours to propagate, affecting deliverability to stricter inboxes like Outlook.
20 Apr 2022 - Klaviyo Help Center
Technical article
Documentation from Klaviyo Help Center outlines that emails may not deliver if the new sending domain has not been fully verified within Klaviyo. Even if DNS records are updated, the platform needs to recognize and confirm these settings. An unverified domain will lead to deliverability issues, including failed test sends to Outlook.
12 Aug 2024 - Klaviyo Help Center
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