The rise of security threats in the online world today is an ever-present danger for website owners and visitors alike. It is critical to make certain that the traffic exchanged between our browsers and the intended websites is properly secured by a trusted encryption layer to prevent anyone from eavesdropping the information that can easily lead to financial and/or identity theft, stalking, or worse…

The way browsers secure traffic is through the use of an SSL certificate chain. This is a unique key exchange between a visitor’s browser, the target website, and the certificate authority who issued that certificate. This exchange ensures that any information submitted to the website is fully protected and that only the legitimate recipient is able to decrypt that data. This way, even if one falls victim to a Man-in-the-middle Attack, the hacker only receives scrambled garbage that would take an uncountable number of years to crack open. 

In this article, we will discuss the implications, variations, and possible resolutions for an invalid certificate authority error message commonly displayed in browsers as error code:

What is a certificate authority?

To understand the invalid Certificate Authority (CA) related error codes we must start with a simple definition. The CA is a trusted third party that issues SSL certificates for websites. They act as an arbitrator between the webserver and the visitor’s browser, legitimizing the security of the data encryption layer. Similar to how eBay acts as a broker between sellers and buyers. The CA can validate whether the browser and the website are the legitimate parties involved in the exchange of information. SSL certificates cannot work without a trusted CA backing the connection. So it is very important that the CA involved in the key exchange is the correct trusted party. Website security the world over cannot work without Certificate Authorities.

What is an Invalid Certificate Authority?

The error code in question is displayed by the browser in an effort to alert the user to a critical level security threat. This occurs when the browser cannot determine if the authority of a certificate in question is valid and can be trusted. An individual certificate can be deemed invalid by the browser if any of the following are true during the key exchange:

1. The certificates validity start date/time has not been reached yet.
2. The certificates expiration date has come to pass.
3. The authorities Root certificate is missing, expired, or revoked from either side of the connection.
4. The intermediate certificate is missing, expired, or revoked from the server-side connection.
5. The private key used to issue the certificate is missing from the server-side connection.
6. The domain in the browser address bar does is not listed in the certificates common name field.

Certificate Authorities use a unique set of trusted encryption keys called Root and Intermediate certificates. Together these special certificates make up what is referred to as the CA Bundle (ca-bundle). The bundle must be present on the server-side of the connection. If it is missing or invalidated by an error, the browser cannot trust the connection and will throw the invalid certificate error code appropriate to the browser in question.

The list of trusted authorities is installed and maintained as a part of the operating system and browser applications. It is most frequently used by browser vendors to verify which authorities are currently trustworthy and therefore valid.

What causes invalid certificate authority errors?

There are a handful of known problems that occur in the wild that can result in visitors encountering this type of security problem.

1. The CA’s Root certificate is missing on either end of the connection (browser-side or server-side).
2. The CA’s Intermediate certificate is missing on the server-side of the connection.

The two most common causes for a broken trust chain is when a certificate in the chain becomes expired. Which can happen to any of the key components of the trust chain i.e.: root certificate, or its intermediate certificates. All certificates in the trust chain must be valid for the browser can be certain that the data is secure. When one of them is returned an invalid state, there is no way of knowing if that segment of the chain was compromised and thus is treated as suspect. 

In order for any SSL certificate exchange to work properly, there are three key aspects that make up the encryption layer between modern browsers and the visited website.

These three aspects of this encryption layers are: 

1. The visitor’s browser – i.e. Chrome, Firefox, Microsoft Edge, Opera, Safari, etc… 
2. The SSL certificate installed on the website or application being visited.
3. The Certificate Authority that issued and validates the website’s SSL certificate. 

All three of these components must be in alignment in order for the encryption to succeed. If one component is out of bounds, it will result in an error like our invalid certificate authority error or similar.

when you see the NET::ERR_CERT_AUTHORITY_INVALID error message, stop and reassess what information you may be sending to the website in question as caution is most certainly warranted here. The best way to ensure your private data is safe is by leaving the site immediately, filing a complaint with the site owner, and seek out an alternative site that doesn’t fail its chain of trust checks.

What are Similar Error Codes?

Before we step through the possible resolution scenarios for this type of problem, let’s go over what this error looks like in the most common browsers available today. We will also identify other similar error codes that browsers may display when they are unable to safely encrypt traffic.

The examples below will show us what the NET::ERR_CERT_AUTHORITY_INVALID error message looks like in the wild so you can more easily recognize it. As well we will list out the similarly related SSL errors that are all commonly resolved using the same troubleshooting techniques provided in this article.

Related Error Codes – These are similar certificate errors that result in the same ultimate outcome, i.e. a broken SSL certificate configuration and a break in the chain of trust provided by the offending certificate authority. These related errors are generally caused by other specific problems with the SSL configuration. However, they are all often resolved by following the exact same troubleshooting steps suggested here.

Fixing Error Code: NET::ERR_CERT_AUTHORITY_INVALID

Troubleshooting an invalid certificate authority error is virtually identical to troubleshooting most certificate errors with websites. There are some problems that can occur on the visitor’s operating system and/or browser that could be interfering with the validation process. Typically, this error is on the web server side of the connection and usually pertains to one or more of the certificates in the chain becoming expired, revoked, or missing.

For specific troubleshooting steps for website visitors and administrators alike, review our companion guide to troubleshooting SSL certificate errors. All the steps in the guide have been known to correct problems with SSL installations or browser and operating system misconfigurations. So you should be able to find a solution for your specific issue with NET::ERR_CERT_AUTHORITY_INVALID, please review the following table of contents for our guide to jump to the specific solutions you’d like to try:

As always, if you’re a NameHero customer and you received a Free SSL certificate, and you are having any of the aforementioned issues with it, please don’t hesitate to open a support ticket or contact us via live chat!