Chinese users of the instant messenger Signal knew that the good times wouldn’t last long. The app, which is used for encrypted conversations, is unavailable in mainland China as of the morning of March 16, a test by TechCrunch shows. The website of the app has been banned in mainland China since March 15, according to censorship-tracking website Greatfire.org.

Signal could not be immediately reached for comment.

The encrypted chat app was one of the few Western social networks that remained accessible in China without the use of a virtual private network. The likes of Facebook, Twitter and Instagram have long been blocked. In some way, a ban is a badge of honor, signifying a foreign app has reached a substantial user base in China that catches the attention of local authorities.

Signal is still available for download on Apple’s China App Store as of March 16, an indication that Apple hasn’t received a government order to remove the app, which is gradually gaining ground among China’s tech-savvy, privacy-conscious users. The app has 4.9 out of 5 from 37,000 ratings on the Chinese App Store.

Android stores in China are operated by a slew of third-party Chinese tech firms, which tend to comply strictly with local censors and don’t list Signal. Google Play is unavailable in the country.

The iOS version of Signal has been installed close to 510,000 times to date in China and recently crossed 100 million downloads across Apple’s App Store and Google Play combined globally, app analytics firm Sensor Tower told TechCrunch on March 16.

Signal and rival Telegram have seen a surge in downloads after WhatsApp’s updated privacy policy sparked panic among users in January. While the impact is limited in China, where Tencent’s WeChat commands a formidable share in social networking with 1.1 billion monthly users, both Signal and Telegram have seen small user upticks in China.

As of January, Telegram had amassed about 2.7 million installs on China’s App Store, compared to 458,000 downloads for Signal and 9.5 million times for WhatsApp. Like Signal, both Telegram and WhatsApp are still present on the China App Store, though access appears to require virtual private networks.

China’s elaborate Great Firewall has made many internet users experts on censorship circumvention. App bans are often layered as the Clubhouse case shows.

While the drop-in audio app wasn’t found on the Chinese App Store, users discovered ways to install it in foreign App Stores and used it freely without censorship-fighting tools until the app’s API was blocked. Even after that, China-based users realized they could listen once they entered a chat room through a VPN, as Clubhouse’s audio technology provider Agora remains accessible in China.

Foreign apps and websites are occasionally cut off in China and brought back, as with Microsoft’s search engine Bing. It’s unclear whether the Signal ban is permanent, but given the app’s growth, this could mark the end of its short life in China.