diff --git a/app/notify_client/user_api_client.py b/app/notify_client/user_api_client.py
index b1054f769..d6a4ad574 100644
--- a/app/notify_client/user_api_client.py
+++ b/app/notify_client/user_api_client.py
@@ -90,5 +90,5 @@ class UserApiClient(BaseAPIClient):
 
     def add_user_to_service(self, service_id, user_id):
         endpoint = '/service/{}/users/{}'.format(service_id, user_id)
-        resp = self.post(endpoint)
+        resp = self.post(endpoint, data={})
         return User(resp['data'], max_failed_login_count=self.max_failed_login_count)