diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index 9c6f22760d..dc563538de 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -152,7 +152,7 @@ class TransportLayerClient(object):
         # generated by the json_data_callback.
         json_data = transaction.get_dict()
 
-        path = _create_v1_path("/send/%s/", transaction.transaction_id)
+        path = _create_v1_path("/send/%s", transaction.transaction_id)
 
         response = yield self.client.put_json(
             transaction.destination,
@@ -161,7 +161,7 @@ class TransportLayerClient(object):
             json_data_callback=json_data_callback,
             long_retries=True,
             backoff_on_404=True,  # If we get a 404 the other side has gone
-            # try_trailing_slash_on_400=True,
+            try_trailing_slash_on_400=True,
         )
 
         return response