Error code 10066: Unable to authenticate, error sending request
Error code 10066: Unable to authenticate, error sending request popups
10066 is defined as ERCODE_AS_GUI_AUTH_WINHTTP_SEND_REQUEST which is returned to our error handler when we encounter an internal
rErrorSendingWinHttpRequest. This gets returned from a single function WinHttpInterface::send that calls Microsoft’s ::WinHttpSendRequest and
::WinHttpReceiveRequest if ::WinHttpSendRequest succeeded. If either fail we check to see if Microsoft reports an error of ERROR_WINHTTP_RESEND_REQUEST
if we get that we retry until we either succeed or get another error code.
Symantec changed this error to write to the log files and not to be shown as pop up message. This has been fixed in 7.5 SP1 HF6.