Western-run social networks like Facebook, Twitter, and Instagram have been unavailable in the country for some time, but Signal has largely flown under the radar of China's authorities until now. Signal has yet to comment on the issue.
It's unclear what has caused the country's government to act and whether the ban is permanent, however Signal and rival service Telegram have both recently experienced a significant uptick in users following WhatsApp's bungled PR campaign explaining its upcoming privacy policy update.
Like Signal, Telegram and WhatsApp are still listed on the China App Store, although access to the services requires the use of VPNs – another category of apps that local authorities have cracked down on in recent years.
VPNs circumvent China's "Great Firewall" by routing and encrypting internet traffic to servers outside of the country, making them popular with privacy-conscious users who have limited access to online content because of government restrictions.
Article Link: Encrypted Messaging App Signal Stops Working in China