https://margincalculator.angelbroking.com/OpenAPI_File/files/OpenAPIScripMaster.json is null, please help with this

I have suddenly started getting the following error when logging in using username, password, and otp using the API:

File "abc.py", line 327, in test_login_access
    data = angel_obj.generateSession(user_id, password, totp.now())
  File "/home/ubuntu/py37-venv/lib/python3.7/site-packages/smartapi/smartConnect.py", line 239, in generateSession
    id=user['data']['clientcode']
TypeError: 'NoneType' object is not subscriptable

What is going on here?