Issues with jQuery Easy - Joomla! System Plugin
If you are using the useful plugin "System - jQuery Easy" try the follow fix.
This plugin strips the "noconflict" jQuery code. If this plugin is installed on your website, try to disable this parameter (Strip No Conflict Code). Navigate to the plugin parameters, click on the tab "Advanced Site Options (Expert users only)" and choose "Strip No Conflict Code" > "No" from "System - jQuery Easy Plugin".