What causes SparkPost link branding issues and how to fix them?
Michael Ko
Co-founder & CEO, Suped
Published 30 Jul 2025
Updated 15 Aug 2025
6 min read
I've seen many email senders encounter frustrating issues with link branding when using platforms like SparkPost. You set up your custom tracking domain, expect your links to reflect your brand, and instead, you get unexpected redirects or errors. This can really undermine recipient trust and impact your email program's effectiveness.
Understanding why these issues occur is the first step toward a solution. Often, the root cause lies in how your domain's DNS records interact with SparkPost's tracking mechanisms, particularly when it comes to security protocols like HTTPS and HSTS. Let's dive into the common culprits and explore how to get your link branding working seamlessly.
The role of link branding in email deliverability
When you send emails through an Email Service Provider (ESP) like SparkPost, the links within your emails, such as click-tracking links, are often rewritten by the ESP. This allows them to track engagement metrics like opens and clicks. Without custom link branding, these links will typically show the ESP's domain, for example, sparkpostmail.com or spgo.io.
Custom link branding allows you to replace the ESP's default tracking domain with your own subdomain, like links.yourdomain.com. This creates a more consistent and professional appearance for your emails, aligning all elements with your brand. It's a critical component for maintaining trust and authenticity with your recipients.
Beyond aesthetics, custom link branding plays a significant role in email deliverability and sender reputation. When recipients see familiar links, they are more likely to trust and click on them. Conversely, if your links point to generic or unfamiliar domains, recipients and even spam filters might view them with suspicion, potentially leading to emails landing in the spam folder. This is especially true for third-party emails linking to your website.
Implementing link branding correctly also helps in mitigating potential issues if your ESP's shared tracking domains ever get blocklisted (or blacklisted). By using your own dedicated domain, you have greater control over your sender reputation and are less susceptible to the actions of other senders on a shared infrastructure. This can be a key factor in improving your overall deliverability rates.
Common causes of SparkPost link branding issues
Most SparkPost link branding problems stem from misconfigurations in DNS records, particularly CNAMEs, and conflicts with SSL/HTTPS settings or HTTP Strict Transport Security (HSTS). If your CNAME record isn't correctly pointing to SparkPost's tracking servers, your branded links won't resolve correctly, leading to broken links or unexpected redirects.
A frequent issue arises when an organization's primary domain has HSTS enabled. HSTS forces all connections to that domain and its subdomains to use HTTPS, even if the initial request was HTTP. If your SparkPost link branding subdomain is configured to handle HTTP traffic, but your main domain's HSTS policy includes subdomains, browsers will attempt to force HTTPS, which can result in errors if SparkPost isn't set up to serve HTTPS for your branded tracking domain. This is a common scenario that causes issues.
Another common pitfall is the incorrect setup of SSL certificates for your custom tracking domain. For your branded links to load securely via HTTPS, you need a valid SSL certificate provisioned for your tracking subdomain. If this is missing or misconfigured, users clicking HTTPS links will encounter certificate warnings, which can seriously damage trust and lead to deliverability problems. These issues can also cause click tracking links from your ESP to be blocked.
HTTP tracking with HSTS enabled
If your main domain enforces HSTS (HTTP Strict Transport Security) for subdomains, and your SparkPost link branding is only configured for HTTP tracking, browsers will try to force HTTPS, causing errors or warnings.
Broken links: Links may fail to resolve or redirect.
Incorrect CNAME or SSL setup
Mismatched or missing DNS records (CNAME) or improper SSL certificate provisioning for your custom tracking domain lead to branding failures.
CNAME points incorrectly: Links don't resolve to SparkPost.
SSL certificate absent: HTTPS connections fail.
Brand inconsistency: Links appear unbranded or generic.
Troubleshooting and fixing SparkPost link branding
The first step in resolving link branding issues is to verify your CNAME record. Log into your domain registrar or DNS provider and confirm that the CNAME record for your chosen tracking subdomain (e.g., links.yourdomain.com) correctly points to the SparkPost provided hostname, such as eu.spgo.io. Any typos or incorrect values here will prevent your branding from working.
Next, address the HTTPS and HSTS aspects. If your primary domain or the tracking subdomain itself has HSTS enabled, you must ensure that your SparkPost tracking domain is set up to handle HTTPS traffic. SparkPost provides options for enabling HTTPS engagement tracking. If self-service HTTPS setup isn't available or compatible with your specific HSTS configuration, you might need to implement a reverse proxy or use a Content Delivery Network (CDN) like Cloudflare or AWS CloudFront. This allows you to terminate SSL at your end and then forward the traffic to SparkPost over HTTP. SparkPost has documentation on using a reverse proxy for HTTPS tracking domains.
If you're still facing problems after checking DNS and SSL, review SparkPost's documentation on enabling HTTPS engagement tracking. It outlines the specific steps required to ensure your tracking domain is properly configured for secure connections. Remember that consistent branding between emails and websites is key for deliverability. Sometimes, issues can also arise from unexpected redirects or even your emails going to spam due to other factors like DMARC.
Best practices for sustained link branding
To prevent future SparkPost link branding issues, proactive monitoring and adherence to best practices are crucial. Regularly verify your DNS records, especially after making any changes to your domain or ESP settings. Ensure your SSL certificates are up-to-date and correctly provisioned for your tracking subdomains.
Additionally, maintain a healthy sender reputation. This involves consistently sending relevant content, managing your email lists effectively, and avoiding activities that could lead to your domain or IP address getting placed on a blocklist (or blacklist). A strong sender reputation helps ensure your emails, including branded links, reach the inbox reliably. Understanding your email domain reputation can provide significant insights.
Views from the trenches
Best practices
Always verify your CNAME records carefully, ensuring they point to the correct SparkPost tracking hostname.
Prioritize HTTPS for all branded links to ensure security and improve recipient trust.
Consider using a CDN or reverse proxy to manage SSL for your tracking domain, especially with HSTS.
Regularly monitor your domain's health and ensure email authentication records are correctly configured.
Keep your SparkPost account and domain settings aligned with their latest recommendations.
Common pitfalls
Forgetting to enable HTTPS for link tracking when HSTS is active on your root domain.
Incorrectly configured CNAME records that prevent proper resolution of branded links.
Ignoring SSL certificate expiry dates for custom tracking domains, leading to warnings.
Not understanding how a shared HSTS policy can affect subdomains used for link branding.
Attempting to troubleshoot without consulting SparkPost's official documentation on tracking.
Expert tips
Use a DNS checker tool to quickly diagnose CNAME and SSL status for your tracking domain.
Implement DMARC for comprehensive email authentication and reporting to catch deliverability issues early.
If self-service HTTPS setup is problematic, consider third-party CDN services as an alternative.
Test your branded links across various email clients and browsers to catch rendering issues.
Set up alerts for changes to your domain's DNS records that could impact link branding.
Marketer view
Marketer from Email Geeks says: I was getting redirect errors, and it turned out to be related to SSL being turned on with the link or perhaps HSTS.
2020-11-18 - Email Geeks
Expert view
Expert from Email Geeks says: If your domain has HSTS with "IncludeSubDomain" enabled, you might need a reverse proxy to handle SSL for your tracking links.
2020-11-18 - Email Geeks
Bringing your brand to every click
Resolving SparkPost link branding issues often comes down to meticulous DNS configuration and understanding how SSL, HTTPS, and HSTS interact with your custom tracking domain. By ensuring your CNAME records are accurate and implementing proper HTTPS solutions, whether directly through SparkPost or via a reverse proxy, you can maintain a consistent brand experience and significantly improve your email deliverability.
SparkPost link branding is only configured for HTTP tracking, browsers will try to force HTTPS, causing errors or warnings.
Cloudflare or 
AWS CloudFront. This allows you to terminate SSL at your end and then forward the traffic to SparkPost over HTTP. SparkPost has documentation on using a reverse proxy for HTTPS tracking domains.
