Since upgrading to 13.3x - now seeing this in my error log.
[2015.04.10] [CurrentUser: ]
[2015.04.10] [4/10/2015 4:17:12 PM]
[2015.04.10] PING sent response for email@example.com / e9c867d1087649a188c631322dcc872f
Does anyone know what this means?? Wouldn't routinely check the error log, but we now have an issue on Chrome browsers were we get the 'contact Smarter Mail Administrator - page.,..... about every 45 minutes (for those browsers).