One problem with RECEIVING E-Mails on a private server is that you cannot control what is being sent there, and in many cases, you (as the recipient) will not even know if the information is classified in the first place (only the sender can be reasonably sure of that), unless it is clearly marked...and then it’s too late.
So Hillary’s statement regarding never receiving classified information has to be immediately discounted by investigators as not credible. She may believe that she never received anything classified (although we all know she’s lying)...but even if the investigators really thought she was being truthful in saying it, they know it’s simply not possible for her have cleared every single E-Mail.
She may believe that she never received anything classified ==
She is not qualified to know; not competent to understand content.
Unless it was a video.