How to Solve the Invalid SSL /TLS Certificate Error?

What is an Invalid SSL Certificate Error?

An Invalid SSL/TLS Certificate Error occurs when a browser cannot validate a website’s security certificate because it cannot verify its legitimacy.

This happens mostly because of an expired certificate, a mismatch between the actual domain name and the details contained in the certificate, or an untrusted certificate authority.

Such errors indicate that, for sure, the identification of the website cannot be trusted, which puts the end users at risk of man-in-the-middle attacks or thousands of other types of cyberattacks.

Causes of Invalid SSL/TLS Certificate Error

An expired certificate has a date of expiration. A browser will flag the connection as insecure if a certificate exceeds this date without being renewed.

Expired SSL/TLS Certificate

The most common and frequent cause behind this specific error is that the SSL/TLS certificate linked with the given website has unfortunately expired. Every SSL certificate is assigned a predetermined period of validity.

If the SSL certificate is not renewed during the stipulated time preceding its expiration date, then later web browsers will term it invalid and not worthy of trust.

Also Read: How to Check TLS/SSL Certificate Expiration Date?

Most modern and widely used browsers such as Chrome, Firefox, and Edge will typically display a notification message to the users when they attempt to access a website running on an expired certificate, alerting them to the potential danger of security breaches.

Mismatched Domain Name

It then means that SSL certificates, while issued for a specific and set domain name as part of its verification process to ensure secure online communications.

This will mean the web browser will immediately point to an “Invalid Certificate” error message if an SSL certificate has been issued on a specific domain, perhaps example.com, but being used on a completely different domain, such as example.org.

Also Read: How to Fix ERR_SSL_VERSION_OR_CIPHER_MISMATCH Error?

This is the case because the certificate does not match or comply with the domain name individuals may be trying to access from their computers when surfing the internet.

Untrusted Certificate Authority

An invalid certificate error will eventually be displayed if the browser does not trust or recognize the Certificate Authority that issued the SSL certificate.

This typically occurs with self-signed certificates, where the issuing entity generates and signs its certificates instead of having them signed by a more authoritative authority.

Also Read: Self-Signed SSL Certificate vs. Trusted CA Certificate

It can also occur when the Certificate Authority is not included in the trusted root certificates maintained by the browser necessary for a secure connection.

Incomplete Certificate Chain

SSL certificates are designed to provide a whole chain of trust, which includes the server certificate, as well as any intermediate certificates that may be involved, and the root certificate that anchors this hierarchy.

Also Read: Root Certificates vs. Intermediate Certificates: Difference

If the server does not include all intermediate certificates required or configure the entire certificate chain correctly, web browsers will fail to validate the certificate’s authenticity. Eventually, this lack of verification will result in the appearance of an error message.

Revoked Certificates

In case the security of a certificate is breached or if this certificate is being misused in some way, the issuing Certificate Authority can immediately revoke that certificate.

Also Read: How to Fix NET::ERR_CERT_REVOKED_Certificate Error?

After any certificate gets revoked, it means no web browser will find that certificate trustworthy, and thus, it will throw an error message due to this problem as well. Another way to check the status of the certificates is through revocation checks.

It is done with the assistance of OCSP, which stands for Online Certificate Status Protocol, as well as with the assistance of CRLs, that is, Certificate Revocation List.

Incorrect System Date and Time

The SSL certificate has an expiry time. Now, this becomes quite important when trying to establish secure communication; if the date or time in the system, either on the server or on the client machine, is wrongly set.

When this happens then the browser would interpret that the certificate is expired, when in fact, it is issued rightly by the trusted authority.

Weak or Insecure Encryption Algorithms

When the SSL/TLS certificate uses an encryption algorithm that is believed to be weak or not secure enough according to contemporary standards, the connection that would be established can easily get marked as insecure.

This is especially true when the server supports only the older versions of the TLS protocol, such as version TLS 1.2 or 1.3, which are more geared towards enhanced security capabilities.

In this case, the problem with the SSL/TLS certificate arises, possibly because the client or the user does not support using those no longer considered secure algorithms.

Misconfigured Server

Server misconfiguration or improper SSL/TLS protocol setup leads to certificate errors. For Example, a server so misconfigured that it accepts only the deprecated SSL, which has been superseded and deemed insecure.

Also Read: Top 10 SSL/TLS Misconfigurations, Risks and It’s Solutions

Instead of the newer versions of TLS, which fail to accept the needed cipher suites in place for secure communication, it may cause the browser not to validate the certificate correctly enough, leaving open security flaws.

Self-Signed Certificates

Self-signed certificates can be used during internal tests; however, browsers will not be trusted by default.

Users end up seeing the “Invalid SSL/TLS Certificate” notice on a website with the self-signed certificate, which was issued by a CA that doesn’t happen to be within a trusted group.

Browser Cache Problem

Sometimes, the browser caches information about old certificates. Even though this certificate has already become valid, cached data might bring up an error, such as an invalid certificate. To clear that off, clear the cache in the browser.

How to Fix Invalid SSL Certificate Error?

To fix the Invalid SSL/TLS Certificate Error, you need to address the root cause of the issue. Below are detailed steps for troubleshooting and resolving the error:

Renew Expired Certificates

SSL/TLS certificates have an expiration period, and if a certificate has expired, then this error message will appear. In such a situation, the best solution would be to renew the certificate through your Certificate Authority.

Many CAs provide automated certificate management tools for auto-renewing certificates. If you manage certificates for your server manually, do not forget to remember to track expiration dates to prevent downtime.

Verify Domain Name Matching

In SSL/TLS, SSL/TLS certificates must match exactly to the domain name for which they are issued. An error will occur if it’s issuing a certificate for another different subdomain or domain name.

Hence, prevent this by comparing the domain name in the certificate and comparing it with the site URL; if it doesn’t match, a new certificate will have to be ordered for the correct subdomain or domain name.

Install Trusted Certificates

Installing trusted certificates is understood as knowing that the error SSL/TLS certificate will be generated if an untrusted Certificate Authority issues the certificate. The browsers are so designed that they accept certificates only from known CAs.

It can be corrected by installing CA certificates on your server. When you use a self-signed certificate, you may install it as a trusted root certificate on all client systems, or you should replace it with the certificate issued by a reputable CA.

Complete Certificate Chain

A chain of trust is how SSL and TLS certificates work. Thus, your certificate has to be validated by intermediate and root certificates.

If the server does not configure or send intermediate certificates correctly, the browser may report an error message saying “Invalid SSL/TLS Certificate.”

A complete chain of certificates must be installed on the server, meaning all the intermediate certificates the client uses must be present to validate that chain.

Use a Trustworthy Certificate Authority

When using a self-signed certificate or one issued by an unknown CA, browsers automatically decline the certificate since it cannot validate its authenticity.

Also Read: Self-Signed SSL Certificate Vs Trusted CA Certificate

In this case, replacing the self-signed certificate with one issued by a known Certificate Authority would be best. Some of the well-known CAs are DigiCert, Comodo, and GlobalSign. Let’s Encrypt is a good option if one is looking for free certificates.

Revoke a Compromised Certificate

This should be done immediately in case your private key for the SSL/TLS certificate is lost. A compromised key should decrypt all traffic encrypted by masquerading as your secure traffic. After revoking the compromised certificate, you may apply for a fresh certificate from CA and install it as soon as possible.

Correct System Date and Time

SSL/TLS certificates are only valid for a certain amount of time. If the server’s system time is inaccurate, then it might display as either expired or not yet valid when it isn’t.

Also Read: How to Check TLS/SSL Certificate Expiration Date?

Check your date and time on your server, as does its timezone settings, since minor variances can lead to errors within your SSL/TLS.

Clear Browser Cache or Reset Settings

Browsers cache SSL/TLS certificates to speed up connection times. Sometimes, the cached version may be outdated, leading to an “Invalid SSL/TLS Certificate” error.

Clearing your browser’s cache or resetting its settings can help resolve this. In most browsers, this option can be found in the settings under “Privacy” or “History.”

Update your Server Software

Apache and Nginx are typical examples of web server software and OpenSSL libraries. Outdated versions of such applications have known vulnerabilities that can lead to certificate validation problems; hence, SSL/TLS errors are to be expected. Your server must be kept up-to-date with all software updates.

Verify Server Configuration

Misconfigured settings at the server level due to mismatched cipher suites or disabled protocols can also produce the error.

It’s essential to ensure your server is configured correctly to accommodate SSL/TLS connections, employing only correct versions of protocols (TLS 1.2 or more) and strong cipher suites.

Conclusion

Get reliable SSL certificates at unbeatable prices with CheapSSLWeb. Protect your users and boost your site’s trustworthiness. Act now to save big!