diff --git a/src/transports/WebSocketTransport.ts b/src/transports/WebSocketTransport.ts
index 6f8b34c..f9f9d3d 100644
--- a/src/transports/WebSocketTransport.ts
+++ b/src/transports/WebSocketTransport.ts
@@ -33,7 +33,7 @@ class WebSocketTransport extends Transport {
       if (err) {
         const jsonError = err instanceof JSONRPCError
           ? err
-          : new JSONRPCError(e.message, ERR_UNKNOWN, err);
+          : new JSONRPCError(err.message, ERR_UNKNOWN, err);
         this.transportRequestManager.settlePendingRequest(notifications, jsonError);
         this.transportRequestManager.settlePendingRequest(getBatchRequests(data), jsonError);
         prom = Promise.reject(jsonError);