All airtime process can die abruptly, with no explanation in logs, specially while you are configuring the streams. Two of them can be handled with daemontools : airtime-playout, and airtime-liquidsoap. The last one, airtime-media-monitor, cannot be handled this way. I started it in rc.local, and sometime, i connect with ssh and restart it manually. It is normal that you get an error when using "restart". Instead, use "stop", then "start". The "stop" may scream about the dead process.