diff --git a/src/index.js b/src/index.js
index 4873988..fdb7a7b 100644
--- a/src/index.js
+++ b/src/index.js
@@ -95,7 +95,8 @@ const corsOptions = {
     if (!origin) return callback(null, true);
     if (allowedOrigins.includes('*')) return callback(null, true);
     if (allowedOrigins.includes(origin)) return callback(null, true);
-    callback(new Error('Not allowed by CORS'));
+    logger.warn(`Allowed origins: ${allowedOrigins.join(', ')}`);
+    callback(new Error(`Not allowed by CORS - ${origin}`));
   },
   credentials: true,
 };