FoxESS Community - Owners & Installers Forum

A lot of API is working for me. But I stopped with this issue:

I try to call: /op/v0/device/peakShaving/get
This endpoint has only one parameter: sn

and I receive error: 40257 - Parameter does not meet expectations

Why? Sn doesn't meet exprctations?

On this issue:

2026-05-17 17:28:04: Foxess: send: json={"sn":"xxx","key":"MaxSOC","value":"25"}, url=https://www.foxesscloud.com/op/v0/device/setting/set
2026-05-17 17:28:04: Foxess: received: {"errno":40257,"msg":"Parameters do not meet expectations. Please reenter","result":null}
2026-05-17 17:28:04: ERROR: 522: Foxess error: 40257-Parameters do not meet expectations. Please reenter

or simple Get:

2026-05-17 18:10:44: Foxess: send: json={"sn":"xxx","key":"MinSOC"}, url=https://www.foxesscloud.com/op/v0/device/setting/get
2026-05-17 18:10:44: Foxess: received: {"errno":40257,"msg":"Parameters do not meet expectations. Please reenter","result":null}

You get that it if your device doesn't support peak shaving.

Thank. Understand.

Do you know that is this error:
2026-05-17 19:22:20: Foxess: received: {"errno":44108,"msg":"Unrecognized msg:44108","result":null}

I’ve never seen that. The error messages API should return all known codes, if you’re seeing something not in there then you’d need to reach out to Fox support to ask what it means.

How can I contact Foxess Support who has knowladge about API?

I’d imagine raise a support ticket from within the fox app, or use the fox website.