Cannot retrieve Workspaces using DocumentManagement WSDL

Dears,

We are using a scanning solution that uses a plugin to connect to OpenText Content Server and retrieves available Workspaces, the Plugin authenticates successfully to the Content Server with the Authentication Webservice, but it fails to retrieve the available Workspaces using DocumentManagement WSDL, it keeps giving the below error


RPC Call failed: The server sent HTTP status code 415: Cannot process the message because the content type 'multipart/related;start="<rootpart*6b2a6349-84bd-40b2-8f8c-45dbc1eb6164@example.jaxws.sun.com>";type="application/xop+xml";boundary="uuid:6b2a6349-84bd-40b2-8f8c-45dbc1eb6164";start-info="text/xml"' was not the expected type 'text/xml; charset=utf-8'.


Any help/clue regarding this?