C# MercadoPago SDK: Error 400 | Invalid Request Data

Question

I'm using MercadoPago SDK and trying to create a PreapprovalCreateRequest but I'm receiving this error:

Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware: Error: An unhandled exception has occurred while executing the request.

MercadoPago.Error.MercadoPagoApiException: Error response from API. | Status code: 400 | API message: Invalid request data

This is the code I'm currently using:

PreapprovalCreateRequest paymentRequest = new PreapprovalCreateRequest
{
    ExternalReference = codPagamento.ToString(),
    BackUrl = (siteAddress) + "/api/public/mercado-pago-webhook",
    PayerEmail = usuario.Email,
    Reason = "Teste Assinatura",
    Status = "authorized",
    AutoRecurring = new PreApprovalAutoRecurringCreateRequest
    {
         CurrencyId = "BRL",
         Frequency = 1,
         FrequencyType = "months",
         TransactionAmount = pagamento.ValorBruto,
    }
};

var requestOptions = new RequestOptions
{
    AccessToken = mercadoPagoAccessToken
};

var payment = await new PreapprovalClient().CreateAsync(paymentRequest, requestOptions);