This page answers a number of frequently asked questions and known problems.
There are some possibilities why you are seeing this error:
Your WordPress session has timed out, and you need to log in again.
When you are using the Cloudflare services, make sure to disable the RocketLoader in the Cloudflare settings.
This is because the page builder creates full-width sections where the sidebar needs to be placed within the layout of these sections. This can be done using the Area element in the page builder.
This is most likely caused by a PHP error being thrown. You need to enable the display_errors parameter in your
php.ini. That way error messages will be displayed on your site, so that you can detect the problem.
Another way to check for PHP errors is to have a look at your PHP error log. Your host should have configured PHP to write that information to a log rather than output them on screen.
Please check this guide to PHP error messages for designers for more information.
This might be due to file permission issues. Please take a look at this tutorial to solve file permission issues.
If no CSS is being loaded, this is probably caused by file permission issues in the theme directory. Please take a look at this tutorial to solve file permission issues.
Usually the errors are caused by a combination of multiple WordPress plugins. The browser's debug console will help you identify the scripts and their related files on your web server. Once you have identified the plugin, you can try disabling it to make sure your page works without any errors again.
data-uk-* prefix for the attributes. The data-* attributes are intended for this kind of use, but for YOOtheme Pro we have decided to go with the short form
uk- to decrease file size. They are non-standard attributes and for this reason indicated by the W3C validator. But that's nothing to worry about.
The W3C CSS validator shows a few errors because YOOtheme Pro uses the latest browser features which may not be part of the official CSS specification yet. That's also nothing to worry about.