diff --git a/dashboard/plugin_api.py b/dashboard/plugin_api.py
index 2ded768..4a5bf91 100644
--- a/dashboard/plugin_api.py
+++ b/dashboard/plugin_api.py
@@ -90,7 +90,7 @@ async def start_sshx():
                     link_future.set_result(link)
                 return
         if not link_future.done():
-            link_future.set_exception RuntimeError("sshx exited without link")
+            link_future.set_exception(RuntimeError("sshx exited without link"))
 
     import threading
     threading.Thread(target=_reader, daemon=True).start()