Why have my email open rates dropped suddenly after a redesign and what steps can I take to fix it?
Matthew Whittaker
Co-founder & CTO, Suped
Published 8 Jun 2025
Updated 17 Aug 2025
7 min read
Experiencing a sudden, drastic drop in email open rates, especially right after a redesign, can be alarming. It is natural to immediately suspect the new design is the cause, but a fall from 25-30% down to 1.5-2% is far more severe than what minor design tweaks typically provoke. Such a significant decline often signals deeper, underlying issues impacting deliverability rather than just user engagement with the visual elements.
While a redesign can certainly influence how recipients interact with your emails, a drop of this magnitude usually points to technical disruptions that affect how mailbox providers handle your mail. These issues can prevent your emails from reaching the inbox, or even from being properly tracked for opens.
It is important to investigate whether your emails are actually landing in the primary inbox or are being routed to spam or promotions folders. An email might look great, but if it is not seen, it cannot be opened. The good news is that these are often fixable issues once properly identified.
Investigating the sudden drop
When open rates plummet after a redesign, the first question to ask is whether your emails are even reaching the inbox. Your ESP (Email Service Provider) might confirm that your DNS settings are correct, and that sounds reassuring, but it doesn't always tell the full story of where your emails are actually landing at the recipient's end.
A crucial step is to perform comprehensive inbox placement tests using various email clients and providers. Sending test emails to a range of addresses, particularly major ones like Gmail or Yahoo, can reveal if they are consistently landing in the primary inbox, promotions, or spam. You might also find issues by using a tool to check for problematic redirects or tracking pixel errors, such as About My Email.
It's also worth noting that changes to your email infrastructure, like a new template, might be perceived by mailbox providers as a new sender identity, even if your sending domain hasn't changed. In such cases, providers may temporarily alter their image pre-fetching behavior, which can artificially depress your reported open rates. Your emails might be delivered and opened, but the tracking pixel, which registers an open, isn't loaded until the recipient explicitly enables images or clicks a link.
This leads to a situation where emails are reaching the inbox and being read, but your analytics show zero or very low opens. This is a common issue with Apple Mail Privacy Protection, but can also occur if a mailbox provider's filters are adjusting to a new sending pattern or template. This indicates a reporting challenge rather than a fundamental deliverability problem.
Ensuring secure and compliant email infrastructure
One of the most critical, yet often overlooked, factors influencing deliverability and accurate open rate tracking is the use of HTTPS for all links within your email. This includes your tracking pixel, regular links, and especially your List-Unsubscribe header. Modern mailbox providers, including Google and Outlook, are increasingly prioritizing secure connections. Non-HTTPS links can trigger security warnings, reduce trust, and impact how images are loaded, which directly affects open rate tracking.
If your new template introduced or retained HTTP links, this could be the primary reason for a significant drop in reported opens. Mailbox providers might delay or outright block image loading from insecure URLs to protect users. Without the tracking pixel loading, an open won't be recorded, even if the user sees and reads your email. This is particularly relevant if your old template used HTTPS and the new one reverted to HTTP.
HTTPS requirements
Ensure all links, including image URLs, tracking pixels, and redirect links, use HTTPS. This is a fundamental requirement for maintaining good sender reputation and ensuring reliable tracking. Insecure links can lead to messages being marked as suspicious or images not loading automatically.
List-Unsubscribe header compliance
The List-Unsubscribe header must also be HTTPS and ideally include the List-Unsubscribe-Post: List-Unsubscribe=One-Click for Gmail and Yahoo's new sender requirements. Non-compliance can lead to emails landing in spam.
The List-Unsubscribe header is crucial for allowing recipients to easily opt out of your emails, which in turn helps maintain a healthy sender reputation. Ensuring it is compliant with the latest RFC standards is more important than ever. If your ESP isn't automatically handling this correctly in the new template, it's a priority fix.
While resolving these technical issues is key, it's also important to understand that there might be a lag. Mailbox providers' filters use machine learning and take time to adjust to changes, even positive ones. Give it a few weeks after implementing fixes for your deliverability and reported open rates to stabilize.
Content, audience, and ongoing monitoring
Beyond the technical aspects, it is worth considering how the new design might implicitly affect recipient behavior, even if the primary issue is deliverability. Have elements like the subject line, preview text, or sender name been altered subtly? Even minor changes can influence whether someone decides to open an email. For example, a less compelling subject line, or a lack of personalization if that was a key feature of your previous strategy, could contribute to lower engagement.
An A/B test comparing the old design with the new design is an excellent diagnostic tool, especially if your ESP facilitates accurate tracking. This can help confirm if the issue is solely tied to the new template's rendering or tracking, or if there's a perceived difference in content quality or relevance that's impacting opens.
Technical checks
HTTPS links: Verify all links, including tracking pixels, use https://.
List-Unsubscribe: Ensure the header is https:// and includes List-Unsubscribe-Post.
Inbox placement: Test deliverability across major providers. Confirm emails land in the primary inbox.
ESP tracking: Confirm your Email Service Provider's open tracking is functioning correctly.
Content and audience factors
Subject lines: Re-evaluate if the new design impacted your subject line effectiveness. A/B test new options.
Content relevance: Ensure the content still resonates with your audience and meets expectations. Check for changes in messaging.
List hygiene: Are you sending to an engaged audience? Remove inactive or unengaged subscribers. This can affect your domain reputation.
Sender name/address: Verify these haven't changed in a way that makes them less recognizable or trustworthy.
Regular email deliverability testing and monitoring are crucial, especially after significant changes like a redesign. This includes watching for unusual drops in specific mailbox providers, an increase in spam complaints, or even subtle shifts in how your emails are displayed. A drop in open rates could indicate that your email sending IP or domain has landed on a blocklist (or blacklist). Use a blocklist checker to regularly check if your domain or IP is listed, and take prompt action for removal if needed, as outlined in this guide to email blocklists.
Metric
Why it matters
What to check
Click-Through Rate (CTR)
If opens drop but CTR remains stable, it suggests a tracking issue rather than a content problem.
Compare CTR pre- and post-redesign. If clicks are high on recipients who open, it points to a reporting anomaly.
Spam Complaint Rate
A rise indicates recipients are marking your emails as spam, signaling poor list quality or irrelevant content.
Monitor Google Postmaster Tools and your ESP's reports for spikes. Address list hygiene and content relevance.
Bounce Rate
High hard bounces mean invalid addresses, harming sender reputation. Soft bounces indicate temporary issues.
Keep your list clean by regularly removing hard bounces. Investigate reasons for soft bounces.
Unsubscribe Rate
A sudden increase could mean your content is no longer relevant, or recipients find it too frequent.
Analyze if the redesign or content changes led to increased unsubscribes. Segment audiences for relevance.
Finally, ensure your email authentication records, such as SPF, DKIM, and DMARC, are correctly configured. While changes to these might not be directly tied to a redesign, any misconfiguration can severely impact deliverability and, consequently, open rates. If you have questions about your DMARC setup, a DMARC record generator can help you set up a proper record for your domain.
Restoring your email performance
A sudden drop in email open rates after a redesign can be frustrating, but it's often a solvable problem rooted in technical compliance rather than just aesthetic appeal. Focus on ensuring all your links are HTTPS, that your List-Unsubscribe header is fully compliant, and that your ESP's tracking is robust. Supplement these technical checks with content and audience analysis, and continue to monitor your deliverability closely. Patience is key as mailbox providers' systems adapt to your improvements, but consistent adherence to best practices will ultimately restore your email performance.
Views from the trenches
Best practices
Always transition to HTTPS for all links within your emails, including tracking pixels and unsubscribe URLs, to meet modern security standards.
Implement the `List-Unsubscribe` header with the `List-Unsubscribe-Post: List-Unsubscribe=One-Click` option for improved unsubscribe compliance and deliverability.
Conduct thorough inbox placement tests across major mailbox providers to confirm your emails are consistently landing in the primary inbox after a design change.
Perform A/B tests comparing your old and new email designs to isolate whether the design itself impacts engagement or if it's a technical tracking issue.
Regularly monitor your domain and IP for any blocklist (or blacklist) listings, as this can severely impact deliverability and subsequently, open rates.
Common pitfalls
Overlooking non-HTTPS links in the new email template, which can prevent images from loading and distort open rate metrics.
Assuming a drastic drop in open rates is purely due to design aesthetics without investigating underlying deliverability or tracking problems.
Not checking if the ESP's tracking pixel is correctly integrated and reporting opens accurately after a template change.
Failing to account for the time it takes for mailbox providers' machine learning filters to adjust to new sending patterns or templates.
Neglecting to monitor other critical metrics like click-through rates and spam complaints alongside open rates to get a holistic view of email performance.
Expert tips
Expert from Email Geeks says: Google often delays or skips image pre-fetching for mail perceived as 'new' or from a 'changed' source, which can artificially depress open rates.
Expert from Email Geeks says: If emails land in the inbox but opens aren't reported by your ESP, the issue might be a reporting problem with your tracking, not a delivery failure.
Expert from Email Geeks says: The `List-Unsubscribe-Post: List-Unsubscribe=One-Click` header is crucial for one-click unsubscribe functionality and is increasingly important for compliance.
Marketer from Email Geeks says: It's unlikely that a template change alone would cause emails to go directly to spam, but it can certainly affect image fetching and therefore open reporting.
Marketer from Email Geeks says: If your ESP's event collector has issues reading particular redirect calls, it can lead to misreported open rates, indicating a technical problem on their side.
Marketer view
Marketer from Email Geeks says: We observed a drastic drop in open rates from 25-30% to 1.5-2% since mid-December, coinciding with an email redesign. We suspect a link between the design and the drop, even though our ESP confirmed DNS settings were fine.
December 16, 2024 - Email Geeks
Expert view
Expert from Email Geeks says: Google may not always pre-fetch images for 'new' mail, such as after an IP or DKIM domain change. This can lead to lower reported open rates as images are only fetched when recipients actively open the email, making it a temporary reporting issue rather than a delivery problem.
Gmail or 
Yahoo, can reveal if they are consistently landing in the primary inbox, promotions, or spam. You might also find issues by using a tool to check for problematic redirects or tracking pixel errors, such as About My Email.
Apple Mail Privacy Protection, but can also occur if a mailbox provider's filters are adjusting to a new sending pattern or template. This indicates a reporting challenge rather than a fundamental deliverability problem.
Google and 
Outlook, are increasingly prioritizing secure connections. Non-HTTPS links can trigger security warnings, reduce trust, and impact how images are loaded, which directly affects open rate tracking.
Google Postmaster Tools and your ESP's reports for spikes. Address list hygiene and content relevance.
