Story highlights He said that a lot of the fake news came from Russia and Breitbart

Conway said the biggest fake news in the election was that Trump couldn't win the election

Washington (CNN) The campaign managers for both major presidential nominees decried Thursday the role fake news played in the 2016 election, though Donald Trump's manager Kellyanne Conway used her criticism to include pundits who doubted the Republican nominee's chances.

"I think the biggest piece of fake news in the election was that Donald Trump couldn't win," Conway told CNN's Jake Tapper during a discussion at Harvard Kennedy School's Institute of Politics, referencing the widespread predictions that Trump couldn't win the Electoral College votes he needed.

Robby Mook, Hillary Clinton's former campaign manager, said false or misleading news was "huge problem" his operation faced, including some evidence that the election meddling came from overseas.

"Look, Jake, I think there's a lot of things we need to examine coming out of this election ... I still think we have to investigate what happened with Russia here. We cannot have foreign, and I would say foreign aggressors here, intervening in our elections."

He continued: "The Russian were propagating fake news through Facebook and other outlets, but look, we also had, and this is with all due respect to Kellyanne and her colleagues, look Steve Bannon ran Breitbart News, which was notorious for peddling stories like this."

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