diff --git a/lib/leopard/message_processor.rb b/lib/leopard/message_processor.rb
index fad9bfa..f2cc4b9 100644
--- a/lib/leopard/message_processor.rb
+++ b/lib/leopard/message_processor.rb
@@ -56,9 +56,11 @@ def base_app(handler, callbacks)
         lambda do |wrapper|
           result = execute_handler.call(wrapper, handler)
           process_result(wrapper, result, callbacks)
+          result
         rescue StandardError => e
           logger.error 'Error processing message: ', e
           callbacks[:on_error].call(wrapper, e)
+          Dry::Monads::Result::Failure.new(e)
         end
       end