I can’t say for certain but some experience in the electric grid space gives me some of the following reasons:
The circuit they are connected to was faulted
They were transferred to a supply that they are not approved to generate on
If they are a large facility then they might have had a failed communication channel that is used to disconnect them if there’s an issue.
This isn’t an exhaustive list but just some common ones









I would consider zoraxy.
https://github.com/tobychui/zoraxy
Single go binary, works on Windows natively if you need that and somewhat more feature rich than npm (if your not custom writing configs)