InputException: invalid token error when fetching historical data

first I generated session token by using login and then generated access token using:
data = kite.generate_session("xttyxxxxxxxxxxxxxxxxxx", api_secret=key_secret[1])
kite.set_access_token(data["access_token"])

I am able to fetch many details, like kite.instruments("NSE") etc. but API is failing with error "InputException: invalid token" when I try to get historical data using
kite.historical_data("TCS",from_date,dt.date.today(),"5minute")

same code was working fine, issue occurring since last night.