diff --git a/serve/mlc_serve/engine/async_connector.py b/serve/mlc_serve/engine/async_connector.py
index 794bc759bd..4819bb3667 100644
--- a/serve/mlc_serve/engine/async_connector.py
+++ b/serve/mlc_serve/engine/async_connector.py
@@ -87,6 +87,7 @@ async def generate(self, request: Request) -> AsyncIterator[RequestOutput]:
             LOG.info("AsyncEngineConnector.generate iterator cancelled.", request_id=request.request_id)
             await asyncio.shield(asyncio.to_thread(self.engine.cancel, request.request_id))
             LOG.info("AsyncEngineConnector.generate request sucessfully cancelled.", request_id=request.request_id)
+            raise
         finally:
             LOG.info("AsyncEngineConnector.generate removing request from result queue.", request_id=request.request_id)
             self.result_queues.pop(request.request_id, None)