HTX.Net.Clients.HTXRestClient.UsdtFuturesApi.Account.GetIsolatedMarginAccountInfoAsync()
method call response is [ServerError] 4002 The merged cross and isolated margin account for USDT-M futures is unavailable.Please complete the query with linear-swap-api/v3/unified_account_info]
seems that HTX switched to new v3 API call and lib does not support it.