"cURL error 60" when trying to update WordPress

Problem

On older versions of WordPress (before version 5.2.21), you may encounter the following error when trying to update:

Download failed. cURL error 60: SSL certificate problem: unable to get local issuer certificate

This would occur because the ca-bundle.crt file included with WordPress 5.2.21 (and older) has expired.

What is a ca-bundle.crt?
In short, it is a file that contains multiple Certificate Authority certificates, which are used to establish a chain of trust for SSL connections. It helps ensure that the server's certificate (WordPress.org) is valid and trusted by the client (your website).

So what happened? 
The ca-bundle.crt file, just like any other SSL-related file, expire after a certain period of time. 
Because of this, the 'trust' between the website and WordPress.org (where updates, plugins and themes come from) was broken, resulting in the cURL error 60 error.

Solution

In order to resolve this, you will need to manually update one file via FTP. 

FTP (File Transfer Protocol) is a method used to download and upload files to/from the server.
You will need an FTP client (Such as FileZilla) to use FTP.

Once you have an FTP client installed, you will need to connect to the server.

• Where do I find my FTP details to connect to the server?

If you have used the Application Vault / Web Applications to install WordPress, the website files would be located in a different folder

• Location of files for applications installed through Application Vault / Web Applications

Once you have connected to FTP and navigated to the folder where your WordPress files are, go into the following folder:

• wp-includes >> certificates
• The only file here is the ca-bundle.crt file, delete this.
• Go to this page: https://github.com/WordPress/WordPress/blob/master/wp-includes/certificates/ca-bundle.crt
• Click the 'Download raw file' button, on the top right of this page. The file will be called ca-bundle.crt

• Upload this file to the wp-includes >> certificates directory.
• Go back into your WordPress Admin Panel and you should be able to update now.

We would advise consulting with your Web Developer on updating your website if you are having any issues.
 

Further Queries

If you have any queries on this, please contact our Support team - see the following for our contact details:

• https://www.blacknight.com/contact-us.html