This message has been reported when using IE 11 to connection to an HTTPS site served by CompleteFTP.
It is extremely uninformative, but it turns out that the problem is related to the
POODLE vulnerability in SSL 3.0. If SSL 3.0 is enabled in CompleteFTP, IE gives this error message.
The solution is simple - upgrade to 8.1.3 or higher versions of CompleteFTP, where SSL 3.0 is disabled by default.
