Popular game streaming platform Twitch is now blocked in China after it experienced a surge in popularity there. The website is no longer accessible inside mainland China and the app has quietly disappeared from the Apple App Store, according to Abacus News.

A Twitch representative confirmed the service is blocked in an email to Variety Friday morning, but didn’t explain why. But, Abacus said the move comes just a month after the app skyrocketed in popularity, becoming the third most-popular free app on the App Store. A large number of Chinese esports fans apparently flooded the service looking to watch the latest Asian Games. This was the first time esports were included in the international sporting event. It was featured as a demonstration sport, which means medals won during matches didn’t count in the official overall medal tally.

Twitch is arguably the most popular destination for video game streaming. Last year, it had over 15 million unique daily visitors who watched an estimated 355 billion minutes of video. This is partly thanks to the massive popularity of Epic Games’ battle royale title “Fortnite” and top streamer Tyler “Ninja” Blevins, who is the first person to reach 10 million followers on the platform. But, its reach in China was limited because it was significantly slower inside the country, according to Abacus.

Some are saying this move doesn’t bode well for Valve, who recently partnered with publisher Perfect World Entertainment to officially bring digital video game storefront Steam to China.

China is currently the world’s biggest video games market, valued at more than $25 billion in 2016, according to a report from IHS Markit. It reportedly represents a quarter of all money generated by video games worldwide.