Much has been made of how the pre-election polls were way off and that somehow that was a reflection of a liberal media bias. Yes, just about every poll had Hillary winning and the Trump's victory was shocking to many. If Hillary had lost the popular vote, a better case could be made that there were some real problems with the polls. That would have showed a wider gap than usual between pre-election polls and the results.
Most polls on the eve of the election had Hillary ahead by about 3-4 points. Here is a post from fivethirtyeight.com which showed a 3.3% lead based on a national average: https://fivethirtyeight.com/features/trump-is-just-a-normal-polling-error-behind-clinton/.
Historically, the margin of error for Presidential polls has been around 2%. Hillary ended up winning the popular vote by 2.1% which reflected a 1.2% poll discrepancy -- less than historical average and certainly less than the 2.7% margin difference from 2012.
The media got a lot of things wrong including some of the polling in critical states in the rust belt, but as far as the national polls were concerned, they polls were pretty accurate and there was no bias.