ERR_CERT_AUTHORITY_INVALID warning in Plesk | An easy fix

ERR_CERT_AUTHORITY_INVALID warning in Plesk giving you trouble? Read on for a simple solution by our in-house experts.

At Bobcares, we offer solutions for every query, big and small, as a part of our Server Management Service.

Let’s take a look at how our Support Team recently helped a customer  deal with ERR_CERT_AUTHORITY_INVALID warning in Plesk.

What is the ERR_CERT_AUTHORITY_INVALID warning in Plesk?

Have you been facing the ERR_CERT_AUTHORITY_INVALID error while attempting to access websites on Plesk? Furthermore, this error appears more commonly when the website has a Let’s Encrypt certificate.

Interestingly, this error also forces the certificate DST Root CA X3 to be shown in the certificate chain.

The error is due to an expired DST Root CA X3 root certificate. This tends to affect the outdated client operating systems like:

• Windows 7
• Windows lower than XP SP3
• iOS lower than 10
• macOS lower than 10.12.1
• Ubuntu lower than 16.04
• Android lower than 7.1.1
• Debian lower than 8

How to resolve ERR_CERT_AUTHORITY_INVALID warning in Plesk

Our Support Team recommends installing the latest updates for the computer or mobile device that we are using to access the websites.

• For Plesk on Windows Server:

  We have to install the latest OS updates and then reboot the server. This helps refresh the root certificates cache.
• On supported Linux OS:

  If the Linux server is in use and it is up-to-date, we do not have to take any further action.
• For Plesk on outdated Linux OS:
  1. First, we have to connect to the server via SSH.
  2. Then, we will open the /etc/ca-certificates.conf file for editing.
  3. Next, we will comment the mozilla/DST_Root_CA_X3.crt line in the file by placing the ! symbol at the beginning of the line. Then we will save the file.
  4. Finally, we will execute the following command:

     # update-ca-certificates

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Conclusion

In brief, the skilled Support Engineers at Bobcares demonstrated what to do when we come across a ERR_CERT_AUTHORITY_INVALID warning in Plesk.