In a recent update, cPanel integrated AJAX scripting into the control panel. You may notice this in how menus "slide" and "expand," however it can cause browser incompatibilities.
The error appears similar to "AJAX Failure! I failed 3 times. Please refresh the page and try again." and it shows only in the email account section of cPanel.
This is a problem with Safari, not Cpanel.
Selecting this link should allow you to manage your email accounts in Safari without the Ajax errors.
Alternatively, you can try using Firefox, IE or Chrome browsers.