First, it looks like Clinton broke the US's laws on handling classified information multiple times, each time a felony.
It only looks like that if you don't know much about how classified information works. Read up on it from a source that isn't referring to Hillary Clinton, and then match that up to what she did.
Second, there's a really good chance she created security holes which were exploited, which is what this thread is about.
Where is the evidence that she created security holes which were exploited? An unreliable source is quoted as saying she did? Personally, I wouldn't trust a government server to keep my emails safe from prying eyes.
The last sentence is pretty key to this. We know the State Department email system was breached at least twice while she was Secretary of State.