If you notice that your widgets are displaying this error message, there are a few things you can try to troubleshoot the issue.
First, right-click the error message and click 'inspect' to open the developer tools in the browser.
This should highlight the element in the window where you can try exposing more about the error message.
Copy and paste the message in green and email firstname.lastname@example.org. From there, we will be able to decipher the message to determine the cause.
If the error message specifies SSL certificate problem, as shown above, you can try restarting your host, and/or rebooting php-fpm. This will be specific to your hosting company, so check their support resources or contact them directly to see if they can do it for you.
If the error persists after rebooting attempts, try uninstalling the IDX plugin and reinstalling the plugin.