My app fails to authorize another zerodha account

Hi,

When i try to get request_token for another user through my api key and secret, I get the following error.

{
"error_type": "ForbiddenError",
"message": "The user is not enabled on the app.",
"status": "error"
}

But it is working fine for my account. Any setting to be done at account level before it can be accessed via any app developed?

Thanks in advance,
Shankar MR