All error codes

plan_not_found

HTTP 404 Plan not found or not available

What happened

The plan_id you sent is not a plan of the server type in question. It does not exist, it has been withdrawn from sale, or it belongs to a different server type - every plan is bound to exactly one server type.

What to do

Read GET /v1/server-types/{id}/pricing for the server type you are using and send a plan_id from the plans it returns. When you resend a corrected write, use a new Idempotency-Key: the previous key is tied to the previous body and would be rejected.

Retrying

Fix the request and send it again.

How it arrives

{
    "type": "https://docs.fiberax.com/errors/plan_not_found",
    "title": "Plan not found or not available",
    "status": 404,
    "code": "plan_not_found",
    "request_id": "a277dcd1ca652c65"
}

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