The Impact of “Not Secure” Website Warnings on SEO and User Trust

A website displaying a “Not Secure” warning can negatively impact both user trust and search engine optimization (SEO) performance. The appearance of this warning indicates a lack of encryption, potentially exposing sensitive data and leading visitors to abandon the site. While not a dominant ranking factor, the resulting user experience issues can indirectly harm SEO. Addressing this issue involves implementing an SSL/TLS certificate and ensuring proper configuration to establish a secure HTTPS connection.

Understanding the “Not Secure” Warning

The “Not Secure” warning displayed by web browsers signifies that the connection between a user’s browser and the website is not encrypted. According to the source materials, this typically means the site is missing an SSL (Secure Sockets Layer) certificate or it is misconfigured. Without encryption, data transmitted between the user and the website—such as passwords, credit card numbers, or even login credentials—can be intercepted. As of 2025, approximately 98% of U.S. web traffic is encrypted with HTTPS, making HTTP sites stand out as potentially unsafe.

The Connection to SEO

While possessing an SSL/TLS certificate is considered a “lightweight SEO ranking factor” by Google’s John Mueller, its primary impact on SEO is indirect. The source materials indicate that the certificate itself does not have a substantial direct effect on rankings. However, the negative user experience associated with the “Not Secure” warning can lead to decreased user engagement and trust, which can, over time, harm SEO efforts. Search engines like Google prioritize secure websites in their rankings, and an insecure site may experience a drop in visibility and organic traffic.

Reasons for the “Not Secure” Designation

Several factors can trigger the “Not Secure” warning. The source materials identify the following common causes:

Absence of an SSL certificate.
An expired SSL certificate.
Serving mixed content (a combination of HTTP and HTTPS elements on the same page).
Improperly configured redirects.

The materials also note that even with a valid certificate, the warning may persist due to issues such as outdated browser cache, incorrect intermediate certificates, or server-side configuration problems involving outdated TLS protocols.

Steps to Resolve the “Not Secure” Warning

The primary solution to the “Not Secure” warning is to install an SSL certificate from a trusted Certification Authority (CA). This establishes a secure, encrypted connection and changes the website’s URL to begin with HTTPS. Once an SSL certificate is installed, several additional steps are necessary to ensure complete security:

Update Internal Links: All internal links on the website must be updated to point to HTTPS.
Force HTTPS Redirects: Configure the web server to perform 301 redirects, ensuring all traffic is automatically redirected from HTTP to HTTPS.
Update XML Sitemaps: The website’s XML sitemaps should reflect the secure HTTPS URLs.
Address Mixed Content: Ensure all resources (images, scripts, stylesheets) are loaded over HTTPS. Even a single HTTP element can trigger the warning.

The Impact on User Trust and Conversions

The “Not Secure” warning significantly erodes user trust. Customers are less likely to trust a website displaying this warning, potentially leading them to abandon their carts or avoid entering the site altogether. Research suggests that 65% of customers will not return to a site if their confidential information is compromised. This loss of trust can result in decreased conversion rates and a negative impact on the business’s reputation.

Diagnosing Certificate Issues

If a certificate appears valid but the “Not Secure” warning persists, the source materials suggest investigating several potential causes. These include mixed content issues, expired or incorrect intermediate certificates, outdated browser cache, and server-side configuration problems related to outdated TLS protocols. Resolving these complex issues may require professional assistance.

Conclusion

The “Not Secure” warning is a critical issue for website owners, impacting both user trust and SEO performance. While the SSL/TLS certificate itself is a relatively minor ranking factor, the negative consequences of the warning—decreased user engagement, lost conversions, and potential ranking drops—make it essential to address promptly. Implementing an SSL certificate, ensuring proper configuration, and regularly renewing the certificate are crucial steps in securing a website and maintaining a positive user experience.