Unable to get access token

Hi,
Please check why I am getting error while requesting for access token. (Client ID : DR0283)
I tried 3 times - within a minute after getting request token..
Getting same error each time

hecksum

File "C:\Users\USER\Anaconda3\lib\site-packages\kiteconnect\__init__.py", line 581, in _post
return self._request(route, "POST", params)

File "C:\Users\USER\Anaconda3\lib\site-packages\kiteconnect\__init__.py", line 668, in _request
raise(exp(data["message"], code=r.status_code))

TokenException: Invalid session credentials


========================== MY CODE ++++++++++++++++++++++++++++++++++++++++++++

from kiteconnect import KiteConnect

# initialise all variables we need
api_key = "xxxxxxxxxxxxxxxxxxxxxxxx"
client_id = "DR0283"

obtained_request_token = "xxxxxxxxxxxxxxxxxxxxxxx"
api_secret = "xxxxxxxxxxxxxxxxxxxxxxxxxxxx"

kite = KiteConnect(api_key=api_key)

try:
    user = kite.request_access_token(request_token="obtained_request_token",secret=api_secret)
    print("Access Token --> ", user["access_token"])
except Exception as e:
    print("Authentication failed", str(e))
    raise