Sendgrid API 返回 Forbidden C#

Question

I am doing everything as it is shown in sendgrid's documentation

    var client = new SendGridClient(apiKey);
    var from = new EmailAddress("test@example.com", "Example User");
    var subject = "Sending with SendGrid is Fun";
    var to = new EmailAddress("whereiwanttosendemail@mail.com", "Example User");
    var plainTextContent = "and easy to do anywhere, even with C#";
    var htmlContent = "<strong>and easy to do anywhere, even with C#</strong>";
    var msg = MailHelper.CreateSingleEmail(from, to, subject, plainTextContent, htmlContent);
    var response = await client.SendEmailAsync(msg);
    Console.WriteLine(response.StatusCode);

Answer 1

'From' mail should be registered in SendGrid as a verified sender. Settings -> Sender Authentication.