API access to Workflows

I am trying to access workflow and back them up via API calls. I am able to authenticate without any issues but either I do not have the right scope or that data is not exposed? 

Basically trying call via this 

$exportUrl = "$ServerUrl/restapi/v1.0/account/~/workflows/$WorkflowId/export"

Getting this error:-

Error backing up workflow 103 : {
  "errorCode" : "AGW-404",
  "message" : "Resource not found",
  "errors" : [ ]
}

As for JWT scope I have Call Control & Read Accounts.