China just blocked Amazon’s streaming service Twitch

The world’s most popular service for live-streaming video games may have just lost a big potential market.

Twitch, which is owned by Amazon (AMZN), is no longer accessible to users inside China. It has also disappeared from Apple’s (AAPL) iOS App Store in China.

A spokesman for Twitch confirmed Friday that the service, which lets users watch and broadcast video-game playing, had been blocked in China but wouldn’t comment further. The country’s internet regulator, the Cyberspace Administration of China, didn’t immediately respond to a request for comment.

The move comes after the streaming service became the third most popular free app in the Chinese iOS store, according to analytics firm App Annie.

That surge in popularity resulted from Chinese eSports fans using Twitch to watch their country compete in the Asian Games last month, which was the first time the event had featured competitive video gaming. According to Hong Kong-based tech news site Abacus, Chinese fans were annoyed that state-run TV wasn’t covering the event and turned to Twitch in droves.

The Chinese eSports team competing at the Asian Games in Indonesia last month.

The live-streaming service, which Amazon bought in 2014 for almost $ 1 billion, joins a host of other foreign platforms that are blocked by China’s vast censorship apparatus, which is known as the Great Firewall. They include YouTube, Facebook (FB) and Twitter (TWTR).

Twitch was likely to have faced problems in China sooner or later.

Chinese authorities have repeatedly cracked down on live-streaming services, placing tight restrictions on platforms and popular users.

China is notoriously sensitive about foreign companies providing media content in its territory, unless they agree to the type of stringent censorship local firms do. In 2016, Chinese services from Disney (DIS) and Apple were shut down as the government tightened regulations governing online content such as videos, games and books.

The setback to Twitch comes at a time when the Chinese government has started taking a harder line on the gaming industry. Regulators have stopped approving licenses allowing online games to charge customers money.

Last month, the government said it planned to limit the number of new online games and put restrictions on the amount of time children and teenagers can spend playing them.

The moves wiped tens of billions of dollars off the market value of Chinese internet company Tencent (TCEHY), which has a huge gaming business.

China is the world’s largest gaming market, accounting for a quarter of global revenue, according to market research firm Newzoo. The firm forecasts China’s total gaming revenue will reach $ 38 billion this year.