Creating order errors out with: "User or API Wallet 0x.... does not exist"

[instesti]

When trying to create an order (testnet) using an account with 0.2 HYPE and 1000USDC, we're hitting an error where HL says it cant find the account.

import { Hyperliquid } from "hyperliquid";

const sdk = new Hyperliquid({
      enableWs: false,
      privateKey,
      testnet: appConfig.NODE_ENV !== NodeEnv.PROD,
      assetMapRefreshIntervalMs: 10 * 60 * 1000,
    });

const result = sdk.exchange.placeOrder({
      coin: "BTC-PERP",
      is_buy: "buy",
      sz: 1,
      limit_px: 30000,
      order_type: { limit: { tif: "Gtc" } },
      reduce_only: false,
    });
console.log("order", result");

Returns:

order: {
  status: 'err',
  response: 'User or API Wallet 0x95f0436c31abab1938745a338dcad319c26601fc does not exist.'
}