backtest not going back far enough

I'm trying to run the strategy_multiple_datas sample and I have Alpaca Pro and using the default date for the backtest which is 1/1/2015, but it's only going back a few months from present date. I changed 'iex' to 'sip' for the data_feed parameter, and it changes nothing. Does the same exact thing. I'm using 1-day candles so I feel like it should really go back further. Does it work right for anyone else?