Apologies, I copied the wrong URI when testing! Both entity: http://validator.linkeddata.org/vapour?uri=http%3A%2F%2Fwww.wikidata.org%2F… and wiki http://validator.linkeddata.org/vapour?uri=http%3A%2F%2Fwww.wikidata.org%2F… give: * Dereferencing resource URI (without content negotiation) ** 1st request while dereferencing resource URI without specifying the desired content type (HTTP response code should be 200): Failed * Dereferencing resource URI (requesting RDF/XML) ** 1st request while dereferencing resource URI without specifying the desired content type (Content type should be 'application/rdf+xml'): Failed ** 1st request while dereferencing resource URI without specifying the desired content type (HTTP response code should be 200): Failed ---- The graph (not the text) suggests an response of: http: 400 Bad Request: The request cannot be fulfilled due to bad syntax This could be vapours fault, but I fear something is wrong with wikidata. At least the wiki test should simply find an information resource. Note that testing wikipedia works: http://validator.linkeddata.org/vapour?uri=https%3A%2F%2Fen.wikipedia.org%2… Best Gregor