Getting "invalid_request" in apple auth token REST API

Hi,

I integrated sign in with apple in my app and I am trying to get access token from auth token API to send to server side,

I have generated clientsecret with private key using JWT and clientid

Request:

Url: https://appleid.apple.com/auth/token

Header:
Content-Type: application/x-www-form-urlencoded

Param:
clientid - "AppId"
clientsecret - "******"
granttype - authorizationcode

Response:
{
"error": "invalidrequest"
}

but getting invalidrequest what i am doing wrong it couldn't get it?

Please help me to resolve this issue. ThanKs