All error codes

network_required

HTTP 422 At least one network is required

What happened

The server you are creating would have no network interface at all: the request carries neither public_ipv4 nor any entry in networks. Such a server is unreachable once it boots.

What to do

Add public_ipv4 - {"new": true} for a fresh address, {"id": N} for one the project already holds, or {"reuse": true} for any address of yours that is currently free - or at least one private network id in networks. Either one on its own is enough.

Retrying

Fix the request and send it again.

How it arrives

{
    "type": "https://docs.fiberax.com/errors/network_required",
    "title": "At least one network is required",
    "status": 422,
    "code": "network_required",
    "request_id": "a277dcd1ca652c65"
}

Branch your code on code, never on the wording of title.