Error when reading kospi

[quantcn]

hello, very interesting work you've done. I have a problem when runing your code. When runing the following code:
import FinanceDataReader as fdr
import datetime as dt
start_date = dt.datetime(2011,1,1)
end_date = dt.datetime(2021,1,1)

kospi = fdr.DataReader('KS11',start_date,end_date)

I get the following error message, any solution?
Traceback (most recent call last):
File "e:/myquant/Adv_Fin_ML/trading-rules-using-machine-learning-main/test.py", line 7, in
kospi = fdr.DataReader('KS11',start_date,end_date)
File "e:\myquant\venv_quant389\lib\site-packages\FinanceDataReader\data.py", line 41, in DataReader
df = reader(symbol, start, end, exchange, data_source).read()
File "e:\myquant\venv_quant389\lib\site-packages\FinanceDataReader\investing\data.py", line 62, in read
curr_id = self._get_currid_investing(self.symbol, self.exchange, self.data_source)
File "e:\myquant\venv_quant389\lib\site-packages\FinanceDataReader\investing\data.py", line 30, in get_currid_investing
jo = json.loads(r.text)
File "E:\ProgramFiles\Python\Python38\lib\json_init.py", line 357, in loads
return _default_decoder.decode(s)
File "E:\ProgramFiles\Python\Python38\lib\json\decoder.py", line 337, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "E:\ProgramFiles\Python\Python38\lib\json\decoder.py", line 355, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)