Your website displays a “Not Secure” warning in the browser — and you’re wondering why. In today’s web, where users demand safety and trust matters more than ever, seeing that red label in Google Chrome or other browsers sends a loud message: something’s wrong.

In this article you’ll learn the key reasons your website might be flagged as not secure, what that means for your site and visitors, and the exact steps you should take to fix it and restore trust in your online presence.

What “Not Secure” Really Means

When a browser shows “Not Secure” in the address bar, it’s telling visitors that the connection between their browser and your server is not encrypted. That means any data entered—usernames, passwords, payment details—could be intercepted by a malicious actor.

Most often the culprit is the connection using HTTP instead of HTTPS (the “S” stands for Secure), which relies on encryption protocols like TLS or SSL. If your site doesn’t use HTTPS properly, visitors will see the warning, and trust and conversions may suffer.

Recent data shows a significant portion of websites still mix secure and insecure content or lack proper certificates — exposing themselves to risk of data leaks and search engine penalties.

Top Causes Your Website Is Flagged Not Secure

No SSL/TLS Certificate or Improper Installation

If your site uses HTTP exclusively, you’ll likely get the warning. Installing a valid SSL/TLS certificate lets you switch to HTTPS, which encrypts data in transit. Without it, browsers issue the alert automatically.

Certificates expire, domain names change, or the certificate might not match your domain — any of these will trigger the “Not Secure” message.

Mixed Content

Even if your site loads via HTTPS, if some elements (like images, scripts or stylesheets) still load over HTTP, browsers will flag the page as unsafe because part of the page is unprotected.
Mixed content is a surprisingly common issue: your main page might be secure, but embedded assets on it are not — and that breaks the lock icon.

Outdated Software or Plugins

Using an outdated CMS, theme or plugin can create vulnerabilities. While this alone may not trigger the “Not Secure” label, it raises your overall risk and may allow malicious scripts to run which degrade your site’s security posture.

Wrong Server Configuration or Redirect Issues

If your server doesn’t redirect HTTP traffic to HTTPS, or if there are old cached links or hard-coded http:// URLs in your site code, visitors may land on a less secure version and get the warning.

Expired or Invalid Certificate

A certificate that’s beyond its expiry date, issued to the wrong domain, or from an untrusted certificate authority will cause your browser to declare the site insecure.

Why Being “Not Secure” Hurts Your Business

When your site is flagged as not secure you face multiple consequences:

• Visitor trust drops: Users see the warning and hesitate to stay, especially if they need to enter sensitive info.

• Drop in conversions: Online stores, membership portals and lead-generation sites often see fewer submissions because users don’t trust the site.

• SEO penalty: Search engines prefer HTTPS. Sites without it may rank lower and get less organic traffic over time.

• Data breach risk: Without encryption, data passing between your server and visitor’s browser is exposed to interception and tampering.

How to Fix Your Website Security: A Step-by-Step Guide

Install or Renew an SSL/TLS Certificate

Check whether your domain has a valid certificate. If not, acquire one from a trusted Certificate Authority (many hosts include them free) and install it on your server.
Make sure the certificate covers all subdomains you use (www vs non-www).
Set automatic renewal if possible so it doesn’t expire unexpectedly.

Force HTTPS Across Your Site

Configure your server so all requests to http:// get redirected to https:// permanently (301 redirect).
Update your site’s internal links to use HTTPS rather than HTTP to avoid mixed content issues.

Fix Mixed Content on Your Pages

Scan your site for assets that still load via HTTP: images, CSS, JavaScript, fonts, embedded videos.
Update these URLs to HTTPS or host them securely. Use tools or your browser console to identify mixed-content warnings.
Consider enabling HTTP Strict Transport Security (HSTS) so browsers always enforce HTTPS for your domain.

Update Software, Themes, and Plugins

Make sure your CMS, themes and plugins are up to date. Delete inactive or unsupported ones.
Use strong, unique passwords and enable two-factor authentication for admin accounts.

Check Server and Security Settings

Verify your server’s TLS version is up to date (e.g., TLS 1.2 or 1.3) and you’re not using deprecated settings.
Enable HTTPS-only mode if your platform supports it.
Run an SSL/HTTPS scanner to check grade and configuration issues.

Clear Cache and Confirm All Pages Show Secure Padlock

After implementing changes, clear your site and browser caches.
Visit multiple pages to ensure they display the padlock icon and no “Not Secure” label appears.
Test on various devices and networks to make sure nothing’s blocked or misconfigured.

How to Prevent Future Security Warnings

• Use HTTPS from the start when launching any new site or domain.
  • Enable automatic certificate renewal and monitor for expiry.
  • Regularly check for mixed-content issues after adding new assets.
  • Monitor your site’s security headers and server configurations routinely.
  • Keep your CMS and plugins updated and remove unused ones.
  • Use reputable hosting that supports HTTPS and gives you proper control over redirect and encryption settings.

Quick Checklist for Self-Audit

• Does your URL begin with https:// and show a padlock?
  • Are all internal links and assets using HTTPS?
  • Is your SSL certificate valid (not expired, issued to the correct domain)?
  • Does your server redirect HTTP to HTTPS automatically?
  • Do you run the latest CMS version and have no outdated plugins?
  • Have you cleared cache and tested across devices?

Final Thoughts

In your 30 years in the industry you’ve seen countless websites go live without a second thought about security — but today the stakes are higher and the tools easier. A “Not Secure” warning isn’t just a technical hiccup; it’s a trust barrier between you and your visitor. Fixing it isn’t difficult if you follow the steps above.

When you install a valid certificate, force HTTPS, eliminate mixed content, and keep your site updated, you safeguard both your users and your business. The reward? A padlock icon, improved ranking potential, higher user trust—and fewer reasons to worry about that ominous “Not Secure” label.