The app had more than 170 million monthly users in the U.S. The black-out is the result of a law forcing the service offline unless it sheds its ties to ByteDance, its China-based parent company.

The Supreme Court upheld a law today that could ban the wildly popular social media app TikTok in the U.S. starting on Sunday, unless its Chinese owner agrees to sell it before then. The justices unanimously rejected TikTok’s First Amendment challenge and argued that Congress was entitled to effectively outlaw the app for national security reasons.