diff --git a/servant-server/src/Servant/Server/Internal.hs b/servant-server/src/Servant/Server/Internal.hs
index 730e96d5..54bab782 100644
--- a/servant-server/src/Servant/Server/Internal.hs
+++ b/servant-server/src/Servant/Server/Internal.hs
@@ -66,7 +66,7 @@ import           Servant.Server.Internal.ServantErr
 class HasServer layout where
   type ServerT layout (m :: * -> *) :: *
 
-  route :: Proxy layout -> Delayed (Server layout) -> Router
+  route :: Proxy layout -> Delayed (ServerT layout (ExceptT ServantErr IO)) -> Router
 
 type Server layout = ServerT layout (ExceptT ServantErr IO)