couldn't access ServiceDeskPlus On Demand API

couldn't access ServiceDeskPlus On Demand API

What ever API I used, I'm getting the below response

{
  "operation": {
    "name": "GET_REQUEST",
    "result": {
      "status": "Failed",
      "message": " ACCOUNT_REGISTRATION_NOT_CONFIRMED",
      "error_code": 4001
    }
  }
}


Any suggestions regarding this would be great.