First off, I'm really sorry that happened. Having a unit drop out mid set is exactly the kind of thing that should never happen to you on stage, and I get why it felt like a major fail.
A full power off like that, especially after a reboot earlier in the night, usually points to one of two things: power or heat. Good news is both are very fixable, and it is often something in the stage environment rather than the unit itself.
A few things to check and do before your gig:
Power: Plug straight into a known good wall outlet if you can, and make sure the power connector is fully seated at both ends. Try not to share a power strip with high draw gear (amps, powered speakers, lighting), since a dip on that circuit can trigger a reboot or shutdown. If your stage power tends to be flaky, a small battery backup (UPS) is cheap insurance and will ride through any dips.
Heat: Keep a little airflow around the unit, avoid adding other speakers/monitors next to it, and try to keep it out of the direct path of stage lighting or the sun if outdoors. If it was running warm, a thermal shutdown would explain the full power off.
Windows: Do a full restart before the show so it boots fresh, and pause Windows updates for the day so it does not try to restart itself mid set.
Also, you can always reach out to us by phone, text or email for quicker help.
I hope you solved your issue and didn't have any other hiccups with your unit.
