Purchase Requisition Approval via Email

Hello, we are using a PR approval workflow and are sending out the approval and rejection links via email using %Workflow.Link to approve% and  %Workflow.Link to reject%. We created a service SysWorkflowApprovalService.appURLAction using HTTP and have setup the prefix URL in Workflow parameters. Overall our URL looks like 

http://servername:9090/DynamicsAXAif60/EmailApprovalServicesHttp/xppservice.svc/applyURLAction?action=Approve&workflowDocumentId={8C03E510-BDBE-4563-92BF-FFE27BD52375}&userId=6d250930254c449f1a9942c2d3de793ae246ffcc240b25cc04b4b124ad1f724c

We are getting a 404 error when we make this request. We are able to pull up the WSDL successfully.

We are using AX 2012 R3.

Thanks for your help.