An encrypted messaging app used by the Trump administration temporarily suspended its operations Monday after suffering a massive hack. TeleMessage, a platform that archives messages sent through apps like Signal,

TeleMessage, the app that President Donald Trump’s former national security adviser, Mike Waltz, appeared to use to archive his group chats, has suspended all services after hackers claimed to have stolen files from it.

TeleMessage lets users archive their chats in secure messaging apps. However, the hacker reportedly found that TeleMessage’s archived chat logs aren’t end-to-end encrypted, allowing them to access the contents of certain messages, government official contact information, and login credentials for the service’s backend.