One of the unsung ‘water carriers’ of the internet is the Client URL (cURL) library. In fact, almost every ‘thing’ that uses the internet will use cURL. It even has fans beyond our atmosphere. It’s a collection of software that lets you transfer data with URLs, and WordPress uses it when it makes Application Programming Interface (API) request. If this connection between cURL and WordPress REST API times out, you’ll see a cURL error.
While there are lots of different cURL errors, our focus is with error 28 here. Fortunately, there are a number of fixes:
- Deactivate your firewall and security plugins on a temporary basis.
- Make sure your host uses the most current version of the cURL library and associated software.
- Check over and reconfigure your Secure Sockets Layers (SSL) settings.
- Ensure your other WordPress plugins don’t contribute to your issues.
- Contact your host if you can’t find a fix.
While there are lots of different cURL errors, we’re going to talk more about error 28 here. However, where necessary, we’ll also discuss if another cURL error might pop up to surprise you.
1. Disable Your Firewalls and Security Plugins
One way to find out if you have a cURL error is to check the Tools > Site Health page within WordPress. This type of error will often be critical, and WordPress will give error 28 an explicit name.
One of the first fixes you can try is to disable any firewall or security plugin on your site. Of course, you’ll do this through the Plugins > Installed Plugins screen:
Once you do this, carry out the following steps:
- Check the Site Health page again for the error.
- Access the logs for your security or firewall plugin to see which API request caused the problem.
- Alter the settings for your plugin, and reactivate it to ensure the error disappears.
This is often the primary reason for a cURL error, so you’ll want to make sure this isn’t the problem before you look into other solutions.
2. Ensure Your Hosting Provider Uses a Current Version of cURL
There are a number of interconnected libraries and software that makes sure WordPress runs as you’d expect. While cURL is one, your PHP and OpenSSL versions all need to be current.
The good news is you can check this within WordPress. Once again, you can head to the Tools > Site Health screen and check out the Info tab: