Clinton won the popular vote by the amount that polls predicted. She lost the EC due to razor thin margins in some battleground states, which were well within the margin of error of polls in those states.
Everyone thinks 2016 was a miss for polls, it was not. It was a miss for forecasting models that had Clinton at 90%+ chances of winning while her numbers in many battleground states were really tossups.
https://lemm.ee/post/42289858