Are you having errors on the WordPress Site Health screen? Check below to see if your error matches any of the following. This just may be a solution that works for you.

Possible error messages

The following possible notifications can be or are most likely related.

The REST API encountered an error
The loopback request to your site failed

Both notifications give additional information that looks like this:

cURL error 28: Operation timed out after 10000 milliseconds

What does it mean

It is most often caused by a theme or plugin that makes use of PHP SESSIONS. WordPress developers have not supported these from the get-go but user SESSIONS apparently were available up to version 4.9. So if the theme or plugin uses

session_start()

the system hangs after that.

How to solve it

It would be best to ask the developers of the theme or plugin to change the code. If they can/will not or if you are a developer or know how to read code you can edit this yourself. Please make sure you create a backup of the site and the file you are going to edit.

Check the code to see if there is anything like

add_action('init', ...

that is pointing to a function called

session_start()

if so, change it to

session_start( array('read_and_close' => true) );

Save and or upload!

Check the effect

That’s it! Check if your website is still fully functioning and refresh the Site Health screen to see if you have less errors now. Let us know if it worked for you and what plugin or theme was causing this.