From what I could gather, she handled important official emails very poorly. I think she had them stored on a private server and she was discovered. It was an act of incompetence.
They investigated her time and again under very colourful accusations and she came out more or less clean. I'm not American, but to me it feels like they are blowing things out of proportion, like the manufacturoversy of Benghazi, only this time not everything is ludicrous bullshit.
Could you please repeat yourself using the English language?