My hosting provider just notified this to me:
"We have noticed that the "wpmudev-chat" sends an POST request to the admin-ajax.php every 5 seconds. This may be optimized, contact the author for example. As when the chat isn't available on some of the pages, there is no need to call this function."
Can you guys please optimize this plugin when the chat isn't being used in the site. It really helps to bring down server load.