Error message while adding your workflowManager to SharePoint server 2013

If you get the following error message while adding the workflow manager to SharePoint farm
PS C:\Windows\system32> REgister-SPWorkflowService -SPSite "http://mismsvas05:80
80/" -WorkflowHostUri "http://mismsvc2ws01:12291/" -allowOAuthHttp
REgister-SPWorkflowService : Failed to query the OAuth S2S metadata endpoint
at URI 'http://mismsvas05:8080/_layouts/15/metadata/json/1'. Error details:
'The metadata endpoint responded with an error. HTTP status code: Forbidden.'.
HTTP headers received from the server - ActivityId:
57d02aff-9556-4f88-b525-629bf4e5f2a8. NodeId: MISMSVC2WS01. Scope:
/SharePoint. Client ActivityId : 77031a9e-8912-4c66-b6fb-d6866e566d94.
At line:1 char:1
+ REgister-SPWorkflowService -SPSite "http://mismsvas05:8080/"
-WorkflowHostUri "h ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~
    + CategoryInfo          : InvalidData: (Microsoft.Share...WorkflowService:
   RegisterSPWorkflowService) [Register-SPWorkflowService], InvalidRequestExc
  eption
    + FullyQualifiedErrorId : Microsoft.SharePoint.WorkflowServices.PowerShell
   .RegisterSPWorkflowService

The error happened in my case because, the account that I used for WorkflowManager was not a farm administrator. Once I added it as Farm admin, It worked like charm.