Jacy Cao, 25, a media professional working in Shanghai, spent four hours on Clubhouse the first time she logged on, immediately drawn into the freewheeling discussions ranging from technology to politics. However, on Monday night all mainland Chinese users of the audio chat app were blocked, with attempts to log on getting a message that read: “SSL error has occurred and a security connection to the server cannot be made”. On the app itself – which could still be accessed using a VPN – Chinese language discussions around the topic “Clubhouse got GFW‘d”, a reference to the euphemism for the government’s internet control mechanisms, mushroomed.