diff --git a/nilmdb/server/serverutil.py b/nilmdb/server/serverutil.py
index 49b808c..902618b 100644
--- a/nilmdb/server/serverutil.py
+++ b/nilmdb/server/serverutil.py
@@ -123,7 +123,7 @@ def CORS_allow(methods):
         response['Access-Control-Allow-Methods'] = ', '.join(methods)
         # Try to stop further processing and return a 200 OK
         cherrypy.response.status = "200 OK"
-        cherrypy.response.body = ""
+        cherrypy.response.body = b""
         cherrypy.request.handler = lambda: ""
         return