Pandas implemented a separate library for Python called pandas_datareader to facilitate access to a number of APIs for data repositories. Unfortunately, with recent changes to how data is used a number of the functions no longer work. At least one module has been developed to help with this problem: yfinance( formerly fix_yahoo_finance), available from pypi. This is video demonstration of the use of fix_yahoo_finance to download data from, you guessed it, Yahoo Finance.
If for some reason you cannot update pandas_datareader, there is hope for you: yfinance!