Historical data returning null

Hi All,
Below is code snippet , which is returning null when i try to get the historical data
for symbol NIFTY20O1511800PE with Instument token 10526466


SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date from = new Date();
Date to = new Date();
try {
from = formatter.parse("2020-10-07 09:15:00");
to = formatter.parse("2020-10-07 15:30:00");


}catch (ParseException e) {
System.out.println("Begin 01" +e.getMessage());
}

HistoricalData historicalData = kiteConnect.getHistoricalData(from, to, "10526466 ", "60minute", false, true);

Could you pls provide your input.