He knew of her secret server or private server. He asked for her address so they could print they could talk back and forth and he knew it was not. Gov address. Example of this is that he used a pseudonym when talking with Hillary on her private server that was not safe.
He lied about knowing her using her private email service. He said that he learned about it through the news media in 2012. But he was conversing with her on it in 2009 under the pseudonym. Podesto’s emails and her staff emails show this to be true because I spoke that they are very concerned about the lack of security with her server.
Obama knew what she was doing was illegal but directed The doj and the FBI not to prosecute even though they had grounds to prosecute.