The answer to the above question is that Trump's policies were more appealing to working class whites than Hillary Clinton's policies. Clinton won the majority of votes from college educated whites, especially among women. However, there are fewer college educated whites in the electorate than whites without college degrees. Moreover, the strong anti-immigrant sentiment among non college educated whites was a critical factor that allowed Trump to win very close elections in several rust belt states that typically vote for democrats. College educated whites are more supportive of immigration and Clinton campaigned to win their votes. She won their votes but her policies were diametrically opposed to those of non college educated white voters. Republicans are losing college educated white voters while Clinton lost the votes of the larger non- college educated white segment of the electorate.
The social media also played a powerful role in the 2016 election. It made it easier to target angry white voters without college degrees; it also facilitated the use of disinformation programs that focused on cultural issues in addition to economic issues that worry less educated white voters.
This article also makes a powerful case against the use of exit polls to analyze the results of elections. Political scientists never use them because they do not accurately account for the results.