In a recent update from cPanel, they have integrated AJAX scripting. You may notice this in "slide" and "expand" menu.

You may receive error message like "AJAX Failure! I failed 3 times. Please refresh the page and try again." in Safari version 4. It shows only in the email account section of cPanel. At this time it only affects Safari version 4.

cPanel already aware about this problem. They have provided Solution to overcome from this error message. Please refer below article for more details from their official website:

Email Accounts