Error de parseo de Json en servicio de cargos

[osueboy]

Últimamente, en la última semana la librería me esta tirando esta excepción

"Unexpected character encountered while parsing value: <. Path '', line 0, position 0."

El fragmento de código relevante es este

            Customer openpayCustomer = openpay.CustomerService.Get(customer.OpenpayCustomerId);

            chargeRequest.SourceId = request.SourceId;
            chargeRequest.Amount = request.Amount;
            chargeRequest.Customer = openpayCustomer;
            chargeRequest.Method = _cardMethod;
            chargeRequest.DeviceSessionId = request.DeviceId;
            chargeRequest.OrderId = Guid.NewGuid().ToString();
            chargeRequest.Description = request.Description;
            chargeRequest.Currency = DefaultCurrency;
            chargeRequest.Use3DSecure = true;
            chargeRequest.RedirectUrl = request.RedirectUrl;

            charge = openpay.ChargeService.Create(chargeRequest);
            return charge;

al llamar a Create truena con esa excepción, antes funcionaba ese mismo código