diff --git a/Export/Formatter/SpreadSheetFormatter.php b/Export/Formatter/SpreadSheetFormatter.php
index cda326815..7d5eb77aa 100644
--- a/Export/Formatter/SpreadSheetFormatter.php
+++ b/Export/Formatter/SpreadSheetFormatter.php
@@ -573,7 +573,7 @@ class SpreadSheetFormatter implements FormatterInterface
             case 'ods':
                 return 'application/vnd.oasis.opendocument.spreadsheet';
             case 'xlsx':
-                return ' application/vnd.openxmlformats-officedocument.'
+                return 'application/vnd.openxmlformats-officedocument.'
                 . 'spreadsheetml.sheet';
         }
     }