This is the first time this app has been launched in your per-user NGINX (PUN) server. This requires a configuration change followed by a restart of your PUN server. Be sure you save all the work you are doing in other apps that have active websocket connections (i.e., Shell App) and you complete all file uploads/downloads.
Clicking the "Initialize App" button will apply the configuration change and restart your per-user NGINX (PUN) server.
Initialize App