diff --git a/lib/pleroma/web/mastodon_api/mastodon_api_controller.ex b/lib/pleroma/web/mastodon_api/mastodon_api_controller.ex
index e0267f1dc..8279db93e 100644
--- a/lib/pleroma/web/mastodon_api/mastodon_api_controller.ex
+++ b/lib/pleroma/web/mastodon_api/mastodon_api_controller.ex
@@ -1030,6 +1030,8 @@ def render_notification(user, %{id: id, activity: activity, inserted_at: created
       NaiveDateTime.to_iso8601(created_at)
       |> String.replace(~r/(\.\d+)?$/, ".000Z", global: false)
 
+    id = id |> to_string
+
     case activity.data["type"] do
       "Create" ->
         %{