diff --git a/app/models/user.rb b/app/models/user.rb
index 305b7b549cf..07161e8ed01 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -637,7 +637,7 @@ class User < ActiveRecord::Base
   end
 
   def publish_do_not_disturb(ends_at: nil)
-    MessageBus.publish("/do-not-disturb/#{id}", { ends_at: ends_at }, user_ids: [id])
+    MessageBus.publish("/do-not-disturb/#{id}", { ends_at: ends_at&.httpdate }, user_ids: [id])
   end
 
   def password=(password)