How to Fix NET::ERR_CERT_COMMON_NAME_INVALID Error

It is an important security practice to secure your website using HTTPS extension. However, an error message like NET::ERR_CERT_COMMON_NAME_INVALID may appear because of a wrong Secure Sockets Layer (SSL) certificate or browser configuration.

NET::ERR_CERT_COMMON_NAME_INVALID doesn’t prevent visitors from accessing a website. However, the error message will create a poor first impression since the browser will contain a warning that the site may steal users’ private information.

In this article we’ll explain what the NET::ERR_CERT_COMMON_NAME_INVALID error means, why it occurs, and walk you through ten methods to troubleshoot it.

Error code	NET::ERR_CERT_COMMON_NAME_INVALID
Error type	SSL Connection Error
Error variations	Your connection is not private Your connection isn’t private Warning: Potential Security Risk Ahead This site is not secure
Error causes	Invalid SSL certificate Misconfigured redirects Browser extensions conflict Antivirus issues Operating system issues

What Is the NET::ERR_CERT_COMMON_NAME_INVALID Error?

Usually when accessing a website, the browser has to verify the website’s SSL certificate to establish a secure connection. A website with a valid certificate will redirect the request via the HTTPS protocol, the secure version of HTTP.

However, if the NET::ERR_CERT_COMMON_NAME_INVALID error occurs, it means the browser has failed to verify the SSL certificate. Most of the time, this happens because the common name which is written in the SSL certificate doesn’t match the actual domain name.

For example, if you want to install an SSL certificate on your website example.com, the common name should also be example.com.

Domain mismatch is not the only reason why the NET::ERR_CERT_COMMON_NAME_INVALID error occurs. In some instances, the issue may be caused by the site’s address itself and antivirus configuration settings, browser extensions, cache, and more.

Although this error can be tricky to troubleshoot since it has many possible causes, rest assured that there are ways to fix it quickly.

10 Methods to Fix NET::ERR_CERT_COMMON_NAME_INVALID

In this tutorial, we will explain ten methods to solve the NET::ERR_CERT_COMMON_NAME_INVALID error on your website. That said, before you proceed, make sure to check whether your site is inaccessible only for you or everyone else.

1. Make Sure That the SSL Is Set Correctly

A common cause of this error is a mismatch between the common name on your SSL certificate and the correct domain name. To solve the issue, make sure you have installed the correct certificate and configured the SSL properly.

We will show you a step-by-step guide to troubleshoot the error using Google Chrome. If you use a different browser, the process will be similar.

Here’s how to check the SSL certificate configuration:

1. Go to your website and click on the padlock icon on the address bar.
2. From the dropdown menu, select Connection is secure.

3. Select Certificate is valid.

4. A window will open containing the site’s SSL certificate details.

The actual domain name should match the common name listed in the SSL certificate’s Issued to domain information. If that isn’t the case, there is an SSL mismatch error between the two. The only solution is to delete and install a new SSL certificate.

Check Wildcard SSL Configuration

Wildcard SSL certificates can encrypt data on multiple subdomains. Therefore in some cases, the common name inside an SSL certificate is listed as a subdomain like domain.example.com.

If you use a wildcard certificate on your subdomain and encounter the NET::ERR_CERT_COMMON_NAME_INVALID error, it means that your SSL certificate doesn’t cover the subdomain you are trying to access.

Check Subject Alternative Names (SAN) Configuration

A Subject Alternative Names (SAN) certificate allows data encryption on multiple domains pointing to one site address. It covers www and non-www versions of a website, subdomains, and top-level domain (TLD) variations.

If the website you’re trying to access uses a SAN certificate, examine the list of domains it protects by checking the certificate details. If a web address is not there, the certificate doesn’t cover it.

2. Check WWW vs. Non-WWW Versions and If Your Site Is Redirecting to Another URL

It is important to know whether your browser or you are forcing your visitors to another version of your website since not all SSL certificates cover both www and non-www site versions.

For example, if your domain is mydomain.com, and the server redirects your website visitors to www.mydomain.com, the error may appear if there is only one SSL installed for the “www” version.

There are two ways to solve this problem. The first one is to change the common name on the certificate your domain defaults to. The second is to purchase another SSL certificate to cover the domain you’re redirecting from.

3. Ensure WordPress URL Is Directing to the Site URL

In some cases, the web protocol HTTP may have been manually changed to HTTPS without installing an SSL. As a result, the website may encounter a common name mismatch error.

If that’s the case, you should change your WordPress URL:

1. On the WordPress dashboard, click Settings and choose General.

2. Check whether the WordPress Address (URL) and Site Address (URL) match.

3. If they don’t match, make the appropriate changes.

4. Check for Any Browser Extension Conflicts

Having too many browser extensions can cause issues as they may conflict with one another. This may be a possible cause of the common name mismatch error.

Access the website in an incognito window and see if it is reachable. If it is, the problem might be caused by a browser extension. To solve this, disable the extensions one by one while checking your site to determine the cause of the issue. Once you’ve isolated the conflicting extension, delete it.

Here is how to remove extensions from Google Chrome:

1. Click the three dots at the top-right corner.
2. Hover over More tools and select Extensions.

3. Once the new window opens, select the extension you want to uninstall and click Remove.

To prevent this issue from happening in the future, make sure to audit and update your extensions regularly.

5. Clear the Browser Cache

Browser caching is a great feature that stores records of websites you’ve visited so the browser cloud load them faster the next time you visit that specific website.

Unfortunately, outdated cache may cause problems by loading an old version of a website. To prevent this, clear the browser cache regularly. This way, your browser will load the most recent version of the website and prevent the NET::ERR_CERT_COMMON_NAME_INVALID error from reoccurring.

6. Disable Antivirus Software and Firewall

Some antivirus software has an HTTPS scanning feature to add more protection. That said, it may block you from visiting HTTPS sites. If you trust the website, try disabling HTTPS scanning on your antivirus.

If this option is unavailable, you may have to entirely turn off the antivirus software.

Here’s how to disable Windows antivirus software:

1. Click on the Start button and look for Settings.
2. Find Update & Security and choose Windows Security.
3. Open Virus & threat protection and click Manage settings. Finally, switch Real-time protection to Off.

Here’s how to do it on macOS using ESET Endpoint Security:

1. Open Finder and look for the ESET Endpoint Security application.
2. Open the application and click Setup. Switch Real-time file system protection to Disabled.

7. Configure URL Settings In phpMyAdmin

The NET::ERR_CERT_COMMON_NAME_INVALID may be caused by the URL difference between option_value in siteurl and home rows of your website’s database. You can change your WordPress URL settings via phpMyAdmin.

Here’s how to do it via hPanel:

1. Go to your hosting account and open the phpMyAdmin application.
2. Choose your site’s database and find the wp_options table. Inside wp_options, look for siteurl and home rows. Make sure both redirect toward the same URL.

8. Clear the SSL State

When you access a website, the browser will cache its SSL certificate to speed up the load time the next time you visit. This may cause the NET::ERR_CERT_COMMON_NAME_INVALID error later.

This troubleshooting method involves clearing the SSL state in the browser and operating system. The process may differ depending on your operating system and browser.

Here’s how to clear the SSL state on Windows:

1. Navigate to Control Panel -> Network and Internet -> Internet Options.
2. The Internet Properties window will open. Click the Content tab and choose Clear SSL state.

You can also clear the SSL state on your browser. Here’s how to do it on Google Chrome:

1. Navigate to Settings after opening the three dots menu at the top-right corner.
2. Select Security and Privacy and click the Security option.
3. Scroll down and choose Manage certificates to see the list of SSL certificates cached by Google Chrome. Lastly, click Remove to clear the SSL state.

9. Change Your LAN Settings

Proxy settings route web traffic to protect users from malicious third parties. Any misconfiguration may restrict you from accessing websites or even cause SSL errors.

Here’s how to change the LAN settings on Windows:

1. Navigate to Control Panel -> Network and Internet -> Internet Options.
2. Choose the Connections tab and select LAN Settings.

3. Tick the Automatically detect settings option. Save the changes by clicking OK.

Here’s how to do it on macOS:

1. Open Apple menu, click System Preferences, and choose Network. Select a network service from the list and click Advanced. Finally, switch to the Proxies tab.
2. Tick Automatic proxy configuration and save the changes by clicking OK.

10. Update Your Operating System and Browser

It is crucial to update your applications and operating system regularly. Failure to do so can result in software instability, potentially leading to a lot of website errors.

Here’s how to check for Google Chrome updates:

1. Click the three dots at the top-right corner and hover over Help. Select About Google Chrome.
2. The Settings will open, letting you know whether an update is available. If it is, click Update Google Chrome. If you can’t see this button, it means you’re on the latest version.

Follow these steps to update Windows:

1. Go to Settings, then click Update & Security.
2. Choose Windows Update. The system will let you know whether an update is available. You can also manually Check for updates.

Here’s how to check for updates on macOS:

1. Open the Apple menu and select System Preferences.
2. Choose Software Update. Click Update Now if a new version of macOs is available.

How the NET::ERR_CERT_COMMON_NAME_INVALID Error Appears on Different Browsers

Depending on your browser, the common name mismatch error warning message may differ. In this section, we’ll take a look at what it looks like on several popular browsers.

Google Chrome

If you visit a website with an SSL error using Google Chrome, the browser will display the “Your connection is not private” message with NET::ERR_CERT_COMMON_NAME_INVALID under it. Google Chrome also warns visitors that attackers might steal their information through the website.

Google Chrome will recommend users to get Back to safety. That said, it’s still possible to visit the website by clicking on Advanced and choosing to Proceed to the website.

Microsoft Edge

If you encounter the NET::ERR_CERT_COMMON_NAME_INVALID error on Microsoft Edge, you’ll see the “Your connection isn’t private” message along with a warning that accessing the website might invite attackers to steal your personal information.

You will be able to choose whether to Go Back or visit the website by choosing Advanced.

Mozilla Firefox

Mozilla Firefox displays a unique version of the NET::ERR_CERT_COMMON_NAME_INVALID error message. It says “Warning: Potential Security Risk Ahead” and warns the visitor that the browser has detected a potential security threat and did not continue to the website.

Firefox doesn’t indicate the code for the common name mismatch error. Instead, it informs visitors what happened in detail, mentions that the issue is most likely with the website, and provides solutions to the problem.

Opera

When you encounter the common name mismatch error using Opera, the browser displays a similar warning message to Google Chrome and warns you that attackers may be trying to steal your personal information.

The Help me understand button describes why Opera doesn’t let visitors access the website. It says the browser doesn’t trust the SSL certificate used on the website.

Internet Explorer

Internet Explorer keeps its NET::ERR_CERT_COMMON_NAME_INVALID error message simple by stating “This site is not secure” and explaining that someone might be trying to fool the visitor or steal their info. It then warns the user to close the site immediately.

Internet Explorer users can choose to Close this tab or see More information. If you select More information, the browser explains that it doesn’t trust this website’s SSL certificate and displays the error code DLG_FLAGS_INVALID_CADLG_FLAGS_SEC_CERT_CN_INVALID.

Conclusion

SSL is an essential part of a website that is dedicated to protecting users’ data via encryption methods. However, if you’ve misconfigured the SSL settings, you may encounter an error such as NET::ERR_CERT_COMMON_NAME_INVALID.

Dealing with the common name mismatch error can be tricky, but there are many methods to solve it quickly – this tutorial has discussed ten of them. The solutions involve changing the SSL configuration, URL redirection, advanced browser settings, and proxy settings.

We hope this article has helped you troubleshoot the common name mismatch issues. If you have questions or tips, feel free to leave a comment below.

NETT::ERR_CERT_COMMON_NAME_INVALID FAQs

Here are some frequently asked questions about the error.