Understanding “host name does not match server certificate” Error

Welcome, Dev, to this article that will help you understand the “host name does not match server certificate” error. This error message can be confusing and daunting, especially for those who are not familiar with SSL/TLS and web server configurations. However, with the right knowledge and tools, you can easily troubleshoot and fix this error to ensure a secure and seamless browsing experience for your users.

What is SSL/TLS and Server Certificate?

Before we delve into the specifics of the error message, let’s first understand what SSL/TLS and server certificate are. SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are cryptographic protocols that provide secure communication over the internet. These protocols ensure that the data transmitted between the web server and the client (browser) is encrypted and cannot be intercepted by third parties.

A server certificate, also known as an SSL/TLS certificate, is a digital certificate that verifies the identity of the web server and enables secure communication. When a user visits a website, the browser checks the server certificate to ensure that the website is authentic and that the communication is encrypted.

What does “host name does not match server certificate” Error Mean?

The “host name does not match server certificate” error occurs when the host name in the URL does not match the host name specified in the server certificate. This means that the browser cannot verify the authenticity of the website and the communication cannot be secured. The error message may look like this:

Error message	Description
Your connection is not private	The website’s security certificate is not trusted or expired.
NET::ERR_CERT_COMMON_NAME_INVALID	The server certificate is for a different domain name.
NET::ERR_CERT_AUTHORITY_INVALID	The certificate authority is not trusted or not known.

These error messages can cause panic among users and may result in loss of trust and credibility for the website owner. However, this error can be easily fixed by ensuring that the host name in the URL matches the host name specified in the server certificate.

What Causes “host name does not match server certificate” Error?

There are several reasons why this error may occur. Some of the common causes include:

• The server administrator has not properly configured the server certificate.
• The server certificate has expired or is not valid.
• The website has been moved to a different domain or subdomain.
• The user has entered the wrong URL or the link is broken.

Now that we know the causes, let’s look at how to fix this error.

How to Fix “host name does not match server certificate” Error?

Fixing this error depends on the cause. Here are some solutions:

Check Your URL

The first thing to do when you encounter this error is to check your URL. Make sure that the protocol (http or https) and the host name in the URL match the ones specified in the server certificate. If the URL is incorrect, correct it and try again.

Check Certificate Details

If the URL is correct, check the server certificate details. You can do this by clicking on the “Advanced” or “More Information” button on the error page. Look for the “Subject Alternative Name” field and ensure that it lists the correct domain name(s) and subdomain(s). If the certificate details are incorrect, contact the server administrator to fix it.

Update Certificate

If the server certificate has expired or is not valid, you need to update it. You can do this by getting a new certificate from a trusted certificate authority (CA) or by renewing your existing certificate. After updating the certificate, restart the server and check if the error is resolved.

Check Server Configuration

If the error persists, it may be due to an incorrect server configuration. Check your web server configuration and ensure that the host name specified in the server certificate matches the one in the server configuration file. If they don’t match, update the configuration file and restart the server.

FAQ

What is a server administrator?

A server administrator is a person responsible for managing and maintaining a web server. This includes installing and configuring software, setting up security protocols, and ensuring that the server is running smoothly.

What is a certificate authority?

A certificate authority (CA) is an entity that issues digital certificates and verifies the identity of the certificate holder. CAs are trusted third-party organizations that validate the authenticity of websites and enable secure communication over the internet.

What is a digital certificate?

A digital certificate is a digital file that verifies the identity of the website owner and enables secure communication. It contains information such as the website’s name, owner’s name, public key, and expiration date. Digital certificates are issued by trusted certificate authorities (CAs) and are used to ensure that websites are authentic and secure.

What is a subdomain?

A subdomain is a domain that is part of a larger domain name. For example, in the URL “www.blog.example.com,” “blog” is the subdomain of “example.com.” Subdomains are often used to organize content on a website or to create separate sections for different purposes.

What is HTTPS?

HTTPS (Hypertext Transfer Protocol Secure) is a secure version of HTTP that uses SSL/TLS to encrypt communication between the web server and the client (browser). HTTPS ensures that the data transmitted over the internet is secure and cannot be intercepted by third parties.

Conclusion

In conclusion, the “host name does not match server certificate” error can be caused by several factors, but it is easily fixable. By following the solutions above, you can ensure that your website is secure and that your users’ privacy is protected. Remember to always keep your server certificate up-to-date and to configure your server correctly to avoid this error in the future.