diff --git a/objectifier-module.nix b/objectifier-module.nix
index c1d18df..6db85c6 100644
--- a/objectifier-module.nix
+++ b/objectifier-module.nix
@@ -76,14 +76,14 @@ in {
         ExecStart = let
           bindClause =
             map (addr: "--bind ${addr}:${cfg.port}") cfg.listen-addresses;
-        in concatStringsSep " " [
+        in (concatStringsSep " " [
           "gunicorn"
           bindClause
           "--workers ${cfg.workers}"
           "-k uvicorn.workers.UvicornWorker"
           "objectifier:app"
           "--pid /run/objectifier.pid"
-        ];
+        ]);
       };
     };
   };