diff --git a/src/kemal/helpers/exceptions.cr b/src/kemal/helpers/exceptions.cr
index a463cba..cda5e59 100644
--- a/src/kemal/helpers/exceptions.cr
+++ b/src/kemal/helpers/exceptions.cr
@@ -13,9 +13,9 @@ module Kemal::Exceptions
   end
 
   class CustomException < Exception
-    def initialize(context : HTTP::Server::Context, message : String = "")
-      @context = context
-      @message = message
+    def initialize(@context : HTTP::Server::Context, message : String? = nil)
+      message ||= "Rendered error with #{context.response.status_code}"
+      super message
     end
   end
 end