3588578 - "HTTP OAUTH 2.0 RESOURCE OWNER PASSWORD CREDENTIALS GRANT " call is failing with response code: 400

• The call to retrieve token using PI is is failing in REST receiver, however using POSTMAN, the call is successful.
• In the XPI 50 or 100 you can find one the below errors: 
  Error while processing Authorization request! 
  [EXCEPTION] 
  com.sap.aii.adapter.rest.ejb.common.exception.HttpCallException: HTTP OAUTH 2.0 RESOURCE OWNER PASSWORD CREDENTIALS GRANT call to https://<target:port>/oauth2/v0/token not successful. Error while obtaining authorization code - response code: 400 
  response: 
  "Received vectorized value :grant_type=[\"password\" \"password\"]" 
  Transmitting the message to endpoint <local> using connection SOAP_http://sap.com/xi/XI/System failed, due to: com.sap.engine.interfaces.messaging.api.exception.MessagingException: com.sap.aii.adapter.rest.ejb.common.exception.HttpCallException: HTTP OAUTH 2.0 RESOURCE OWNER PASSWORD CREDENTIALS GRANT call to https://<target:port>/oauth2/v0/token not successful. Error while processing Authorization request!
• The POSTMAN console shows the below logs: 
  grant_type=password&username=InvoiceServiceAdmin%40magicleap.com&password=***&client_secret=***&grant_type=password&client_id=***

SAP NetWeaver 7.5

PI, PO, Netweaver 7.5, Authorization request, Rest, HTTP OAUTH 2.0 RESOURCE OWNER PASSWORD CREDENTIALS GRANT, response code: 400 , KBA , BC-XI-CON-RST , Rest Adapter , Problem