The xml files are based upon xsn or template files. XML is raw data and you need a template for the form's formatting and structure. You need to bind the URL like below:
https://server/sitesname/_layouts/FormServer.aspx?XmlLocation=[%LibraryName:Server Relative URL%]&source=form library path&DefaultItemOpen=1
https://server/sitesname/_layouts/FormServer.aspx?XmlLocation=[%LibraryName:Server Relative URL%]&source=form library path&DefaultItemOpen=1