The host where your app runs had a bit of a hiccup this morning, it had to be rebooted. Things should be fine now!
Single-instance apps are subject to these issues because there’s no redundancy, nowhere for our proxy to route to.
I realize you’re not a developer so maybe this won’t make sense to you, but: if your app can run more than 1 instance with the same data source, you should scale it up to at least 2 instances.