Sunday, July 14, 2024

What are the Most Common Types of SSL Errors and How to Fix Them?

Recurring SSL certificate error warnings can result in significant negative consequences, such as customer attrition, financial losses, and reputational damage. It is crucial to address these warnings proactively in order to mitigate these risks.

SSL (Secure Sockets Layer) and TLS (Transport Layer Security), which came after it, are methods for connecting networked computers in a secure way. The “https://” in a web address shows that they are most often used to protect links between web browsers and servers.

What happens when warnings like ‘Your Connection is not Private,’ ‘The Site’s Security Certificate is Not Trusted,’ etc., appear on your website?  Data suggests that 85% of online shoppers avoid websites marked as ‘Not Secure‘ by Google.

What are the common types of SSL errors, and how can they be fixed? Read on to find out. 

Table of Contents

SSL Certificate Errors
Expired Certificate 
SSL Certificate Not Trusted 
Mixed Content Error
Name Mismatch Error 
Revoked SSL Certificate Error 


1. How to check SSL errors?

Most of the time, checking for SSL problems means looking at the browser’s security settings and the server’s logs. SSL errors generally show up in web browsers like Chrome, Firefox, or Safari as warning messages, padlock icons, or alert pages that make it hard to get to a site.

Most of the time, these messages tell you what kind of SSL mistake happened, such as an expired certificate, a mismatched domain, or a certificate authority that can’t be trusted.

2. What is an SSL port?

An SSL (Secure Sockets Layer) port is a way for a client and a server to send secured data to each other. The main reason to use SSL is to make sure that the information sent between two systems is safe and can’t be spied on or changed.

The usual port for HTTPS (HyperText Transfer Protocol Secure) communication is 443, which is also the SSL port that is used the most. When you connect to a website using HTTPS, your web browser actually uses SSL/TLS (Transport Layer Security, the successor to SSL) over port 443 to encrypt the data flow.

This makes sure that critical information like login credentials, credit card numbers, or any other private data is sent safely.

Standard HTTP, on the other hand, uses port 80 and does not offer security. SSL ports can also be used for apps like email and file transfers that need to send data securely.

3. Who issues SSL certificates?

Certificate Authorities (CAs) are trusted organizations that check the identity of the certificate applicant and give out a digital certificate that proves ownership of a public key.

CAs are in charge of giving SSL certificates. A CA is an important part of web security because it works as a third-party guarantee that the server you are talking to is really the one it says it is.

When you connect to a safe website (HTTPS), your browser checks the SSL certificate that the web server gives you against a list of trusted CAs. If the certificate is valid and comes from a CA that can be trusted, a secure connection is made.

There are many different kinds of CAs, from big names like DigiCert, Let’s Encrypt, and GlobalSign to smaller, more specialized ones. Some groups even have their own CAs for private networks that they run themselves.

SSL Certificate Errors

When the web browser connects to a website, the server will first send a list of SSL certificates to prove its identity. After performing various SSL checks, the web browser will establish a secure connection with the server. 

An SSL certificate error occurs when the web browser cannot verify the SSL certificate installed on the website. In this case, the browser will block the website and show a warning to the user.

For instance – ‘Warning: Potential Security Risk Ahead,’ ‘The Connection is Not Secure,’ etc. 

Expired Certificate 

One of the most common SSL certificate errors occurs if the certificate’s validity has expired. Currently, the validity is 398 days (1 year and 1 month for transition in case of renewal), and certificates cannot be issued for longer than this stipulated period.

When the intermediate and leaf certificates presented to the browser are not within the stipulated validity period, the browser will block the website and show an error message. 

When you do not have a proper Certificate Management System (CMS) that provides visibility into the certificate lifecycle, you may have forgotten/ missed to renew certificates on time. 


  • Update all your immediate and leaf certificates immediately with new valid SSL certs. 
  • Leverage online centrally managed CMS to keep track of certificates and renew them before expiry.

SSL Certificate Not Trusted 

Trusted SSL root certificates are issued by regulated and trustworthy Certificate Authorities (CAs). CAs don’t sign the end-entity certificate from the root to add extra layers of protection.

They will sign and deploy an intermediary certificate used to sign leaf certificates, creating a chain of trust. 

Web browsers have built-in functionality to recognize trusted root SSL certificates. Upon receiving the certificates from the server, the browser will keep chaining the SSL until the trusted root certificate is reached to establish the chain of trust. 

This SSL connection error occurs when the certificate is not approved/ signed by a trusted CA listed in the browser’s built-in list or the server self-signed certificate.

SSL certificate not trusted error occurs when the SSL chain of trust is invalid or incomplete. 


  • Deploy SSL only from reputed and trustworthy CAs instead of self-signed ones or unknown CAs. Self-signed certificates may be useful for the development environment, not the production environment. 
  • Install and deploy intermediate and the server leaf (end-user) certificates in your server. 
  • Ensure that the web server is configured to return all intermediate and leaf certificates.

Mixed Content Error

A Mixed Content Error in the context of SSL certificates is when a web page loaded over a secure HTTPS connection includes resources, like images, scripts, or stylesheets, that are loaded over an insecure HTTP connection.

This creates a security hole because the main page is encrypted but the mixed material is not. This means that it could be spied on or changed.

Web platforms usually let you know about this problem by putting a warning symbol in the address bar or, in some cases, by blocking the mixed content completely.

Because of this, the site might not look like it can be trusted, or it might not work as it should. This defeats the whole point of having an SSL certificate and encrypting the link.

For website owners, fixing a Mixed Content Error usually means finding all the links on the page that don’t use HTTPS and changing them to use HTTPS.

This makes sure that all resources load safely. If you don’t fix problems with mixed material, user security, and trust could be at risk, which would affect both the user experience and the site’s search engine ranking.

This SSL connection error occurs when a secure HTTPS page contains elements loaded from an insecure HTTP page). For instance, an insecure file, image, iframe, flash animation, etc. The browser will display a warning when there is such mixed content. 


  • Update every file, link, canonical tag, image, reference, plugin, add-on, webmaster tool, etc., to their HTTPS version.
  • Ensure all files and elements on your pages are hosted from secure links. 

Name Mismatch Error 

To establish a secure connection with the server, the domain name in the SSL certificate must match the domain name in the browser URL.

When they don’t, the name mismatch SSL certificate error occurs. Even if the certificate is issued for www.example[.]com and the user types, there will be a name mismatch error.

This error may occur when multiple domains and subdomains use the same hosting environment and IP addresses, and the server sends the certificate for the wrong domain. 


  • Ensure that the certificate supports both www and without www versions of the domain name. 
  • If you secure multiple domains and subdomains with shared hosting and IP addresses, consider buying a SAN/ multi-domain SSL. 

Revoked SSL Certificate Error 

A canceled SSL Certificate Error happens when a web browser finds out that the Certificate Authority (CA) that issued a website’s SSL certificate has canceled it.

Certificate revocation is a very important security measure that CAs use when a certificate has been hacked or when the domain it was given for is no longer controlled by the person who originally asked for it.

When a certificate is revoked, it is added to a Certificate Revocation List (CRL), which web browsers and other client programs check regularly. If a client sees a canceled certificate, it will usually show a security warning.

This makes it impossible for the user to get to the site without getting around the warning. This is to protect the user from possible security risks, like info being stolen or changed by bad people.

A Revoked SSL Certificate Error is a major problem that website owners need to fix right away by getting a new, valid certificate to replace the one that was revoked. This will make sure that their web service is safe and secure.

This error occurs when the CA has revoked/ canceled your SSL certificate, which is present in the Certificate Revocation List. The reasons certificates are typically revoked/canceled are:  

  • Certificate compromised before the expiry 
  • Compromised keys 
  • Certificate acquired with false credentials 
  • Wrong keys issued


  • Immediately replace the revoked certificate with a valid one and investigate the reason for revocation. 
  • Continuously monitor the revocation status of your certs using monitoring tools. 

The Bottomline 

SSL certificate errors are damaging to online businesses. Fix these errors instantly to ensure robust security, integrity, and data privacy in transit.

To prevent them, continuously monitor them and provide visibility into the certificate lifecycle using a Certificate Management Console (CMS).

Because of this, a website’s image and security depend on how quickly invalid SSL certificate errors are fixed. Site owners should check their SSL settings regularly and update their certificates when they need to. Users should pay attention to SSL problem messages as a sign to be careful.

For a safe and easy-to-use web experience, you need to understand SSL issues and fix them right away.


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Guru baran
Guru baran
Gurubaran is a co-founder of Cyber Security News and GBHackers On Security. He has 10+ years of experience as a Security Consultant, Editor, and Analyst in cybersecurity, technology, and communications.

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