diff --git a/services/clsi/nginx.conf b/services/clsi/nginx.conf
index 6205bd5294..2290aeb444 100644
--- a/services/clsi/nginx.conf
+++ b/services/clsi/nginx.conf
@@ -86,9 +86,8 @@ server {
   location ~ ^/project/([0-9a-f]+)/user/([0-9a-f]+)/content/([0-9a-f-]+/[0-9a-f]+)$ {
     if ($request_method = 'OPTIONS') {
       # handle OPTIONS method for CORS requests
-      add_header 'Content-Type' 'text/plain charset=UTF-8';
       add_header 'Allow' 'GET,HEAD';
-      return 200 'GET,HEAD';
+      return 204;
     }
     # Cache for one day
     expires 1d;