Flynn was the target of a police state campaign of terror. The history of that period has yet to be written. Given that, I am giving him the benefit of the doubt.
1. He was a paid propagandist for the Islamic regime in Turkey while he was serving as an advisor to Trump's campaign.
2. He was having phone conversations with the Russian ambassador on his cell phone while vacationing in a Third World dump in late December 2016. The content of these calls ended up all over the national news media and eventually precipitated his interview with the FBI.
I try not to be too harsh on the guy, but something about him always suggested that he isn't terribly bright.