diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 897c54b53..522a312c9 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -79,7 +79,7 @@ class PasswordRestServlet(RestServlet):
         new_password = params['new_password']
 
         yield self.auth_handler.set_password(
-            user_id, new_password, None
+            user_id, new_password
         )
 
         defer.returnValue((200, {}))