Not able to upload a document

Not able to upload a document

I am trying to upload a document by calling the upload API ( https://apidocs.zoho.com/files/v1/upload?authtoken=AuthToken&scope=docsapi)

But i am getting below message in the HTTP response 

{"response":[{"uri":"/files/v1/upload"},{"message":"EMPTY_OR_NO_FILE_SPECIFIED"},{"result":[]}]}

Can anyone help me with this error and what does it mean?