diff --git a/lib/transports-uws/polling.ts b/lib/transports-uws/polling.ts
index 98d68f42..1bf01a96 100644
--- a/lib/transports-uws/polling.ts
+++ b/lib/transports-uws/polling.ts
@@ -124,8 +124,8 @@ export class Polling extends Transport {
 
     const contentLengthHeader = Number(req.headers["content-length"]);
     if (!contentLengthHeader) {
-      this.onError("invalid content-length header");
-      res.writeStatus("400 Invalid content-length header").end();
+      this.onError("content-length header required");
+      res.writeStatus("411 Length Required").end();
       return;
     }
     if (contentLengthHeader > this.maxHttpBufferSize) {