Homada.Boumedane
--- a/AoU-Admin/src/main/java/ch/unige/aou/controller/admin/ExportMetadataController.java
+++ b/AoU-Admin/src/main/java/ch/unige/aou/controller/admin/ExportMetadataController.java
    if (!results.getContent().isEmpty()) {
      result = this.exportMetadataService.exportMetadata(exportFormat, results.getContent());
    }
+
    HttpHeaders headers = this.getHeaders(exportFormat);
-    return new ResponseEntity<>(result, headers, HttpStatus.OK);
+
+    // convert the string result to Inputstream
+    InputStream is = new BufferedInputStream(new ByteArrayInputStream(result.getBytes(StandardCharsets.UTF_8)));
+
+    // build the responseBody as stream
+    StreamingResponseBody responseBody = outputStream -> {