diff --git a/jupyter_server_proxy/handlers.py b/jupyter_server_proxy/handlers.py
index 2890dc3a..700e8f5c 100644
--- a/jupyter_server_proxy/handlers.py
+++ b/jupyter_server_proxy/handlers.py
@@ -493,7 +493,7 @@ async def start_websocket_connection():
                 request=request,
                 on_message_callback=message_cb,
                 on_ping_callback=ping_cb,
-                subprotocols=self.subprotocols,
+                subprotocols=self.select_subprotocol(self.subprotocols),
                 resolver=resolver,
             )
             self._record_activity()