Fix “Security Certificate Not Trusted” Error Easily

While browsing the internet, you may encounter an error message stating:

“This server could not prove that its security certificate is not trusted.”

This warning typically appears in modern browsers such as Google Chrome, Microsoft Edge, or Mozilla Firefox. It indicates that the browser cannot verify the authenticity of a website’s SSL certificate.

This issue can be alarming because it relates directly to your online security. Fortunately, in many cases, the error can be fixed with simple troubleshooting steps.

In this guide, we will explain what this error means, why it happens, and how to fix it safely.

What Does “Security Certificate Not Trusted” Mean?

Websites use SSL/TLS certificates to encrypt data and prove their identity. When you visit a secure website (HTTPS), your browser checks the certificate to ensure it is valid and issued by a trusted authority.

If the browser cannot verify the certificate, it displays a warning.

This means:

• The website’s identity cannot be confirmed
• Data transmitted may not be secure
• The connection could be intercepted

Browsers block or warn users to prevent potential security risks.

Common Causes of the Error

Several factors can trigger this message.

1. Expired SSL Certificate

Certificates have expiration dates. If a website owner fails to renew the certificate, browsers will flag it as untrusted.

2. Incorrect System Date and Time

Your computer’s clock plays a key role in certificate validation.

If your system date or time is incorrect, the browser may think the certificate is expired or invalid.

3. Self-Signed Certificate

Some websites use self-signed certificates instead of certificates issued by trusted authorities.

Browsers do not trust these certificates by default.

4. Missing Intermediate Certificates

A certificate chain must be complete. If intermediate certificates are missing, the browser cannot verify trust.

5. Antivirus or Firewall Interference

Security software may inspect HTTPS traffic and replace certificates, causing trust errors.

6. Outdated Browser

Older browser versions may not recognize newer certificate authorities.

7. Network Issues

Public Wi-Fi networks or restricted environments may interfere with secure connections.

How to Fix “Security Certificate Not Trusted” Error

Follow these solutions to resolve the issue.

Method 1: Check Your System Date and Time

Incorrect date and time settings are one of the most common causes.

Steps

1. Open Settings.
2. Go to Time & Language.
3. Enable Set time automatically.
4. Restart your browser.

Method 2: Update Your Browser

Using an updated browser ensures compatibility with modern security standards.

Steps

• Open browser settings
• Check for updates
• Install the latest version

Browsers like Google Chrome update automatically, but manual checks can help.

Method 3: Clear Browser Cache

Cached data may cause certificate conflicts.

Steps

1. Open browser settings
2. Go to Privacy & Security
3. Clear browsing data
4. Restart the browser

Method 4: Disable Antivirus HTTPS Scanning

Some antivirus programs intercept secure connections.

Steps

1. Open your antivirus settings
2. Locate HTTPS scanning or SSL inspection
3. Disable it temporarily

Check if the issue is resolved afterward.

Method 5: Try a Different Network

Network-related issues can cause certificate errors.

Switch to:

• A different Wi-Fi network
• Mobile hotspot
• Wired connection

If the error disappears, the original network may be the cause.

Method 6: Update Operating System

Keeping your system updated ensures that trusted root certificates are current.

For example, users of Windows 11 should install the latest updates.

Steps

1. Open Settings
2. Go to Windows Update
3. Install updates
4. Restart your PC

Method 7: Proceed with Caution (Advanced Users Only)

If you trust the website and understand the risks, most browsers allow you to bypass the warning.

However, this is not recommended unless:

• You know the website is safe
• You understand the risks involved

Avoid entering sensitive information on such sites.

When the Problem Is Not on Your Side

Sometimes, the issue lies with the website itself.

Examples include:

• Expired SSL certificate
• Misconfigured server
• Missing certificate chain

In these cases, there is nothing you can fix locally.

You can:

• Wait for the website owner to resolve the issue
• Contact the website administrator

Security Risks to Consider

Ignoring certificate warnings can expose you to risks such as:

• Data interception
• Phishing attacks
• Malware infections

Always be cautious when encountering certificate errors.

Tips to Prevent Certificate Errors

To avoid similar issues in the future:

Keep Your System Updated

Regular updates ensure proper certificate validation.

Use Trusted Browsers

Modern browsers like Microsoft Edge and Mozilla Firefox offer strong security features.

Avoid Suspicious Websites

Only visit trusted and well-known websites.

Use Secure Networks

Avoid unsecured public Wi-Fi for sensitive tasks.

Conclusion

The “This server could not prove that its security certificate is not trusted” error is a security warning designed to protect users from unsafe connections. While it may seem alarming, it is often caused by simple issues such as incorrect system time, outdated browsers, or antivirus interference.

By following the steps in this guide—checking your system settings, updating your browser, clearing cache, and verifying your network—you can resolve the issue in most cases.

Always remember that certificate warnings exist for your protection. When in doubt, avoid proceeding to untrusted websites and ensure your system remains secure while browsing.