SendGrid SMTP integration issue

Question

I am trying to integrate SendGrid in ASP.NET MVC application using SmtpClient and MailMessage methods on Azure.

Code:

MailMessage message = new MailMessage();
message.IsBodyHtml = true;
message.Subject = "Subject";
message.To.Add("To@MyDomain.com");
message.Body = "Body";
message.From = new MailAddress("From@MyDomain.com", "From Name");

SmtpClient client = new SmtpClient("smtp.sendgrid.net");
client.UseDefaultCredentials = false;
client.Credentials = new NetworkCredential("??", "SG.******");
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.Port = 587; // I have tried with 25 and 2525
client.Timeout = 99999;
client.EnableSsl = false;

client.Send(message);

I end up with this issue both from C# console application and ASP.NET MVC application on Azure VM:

System.Net.Mail.SmtpException: Failure sending mail. ---> System.IO.IOException: Unable to read data from the transport connection: net_io_connectionclosed.

As per the documentation avlb on SendGrid site: https://sendgrid.com/docs/Classroom/Basics/Email_Infrastructure/recommended_smtp_settings.html

The UserName and Password has to : Use the string “apikey” for the SMTP username and use your API key for the password.

I have tried -

1. SendGrid UserName with which I login to their portal

2. The API Key from this page https://app.sendgrid.com/settings/api_keys

3. The password which starts with SG* which is as per their support team.

Any suggestions what am I missing or what which UserName/APIKey should I be using?

Tx!

Answer 1

The link says: Use the string “apikey” for the SMTP username and your API key for the password.

https://docs.sendgrid.com/for-developers/sending-email/v2-csharp-code-example#using-nets-built-in-smtp-library

The username was supposed to be "apikey" and not the actual "api key or api name"

client.Credentials = new NetworkCredential("apikey", 
                                           "<Your API Key which starts with SG.*>");

Adding "apikey" (facepalm) fixed my problem.

Answer 2

According to your description, I guess you may not add the VM outbound role for port 587.

I suggest you could follow below steps to add the role.

Find the network in azure vm portal.

Then find add outbound rule.

3.Add 587 port to outbound role.

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Update:

I suggest you could try to use sendgrid SDK to do this.

I have create a test console application, it works well in my side.

Library: SendGrid

Codes as below:

        var client = new SendGridClient("sendgridkey");
        var from = new EmailAddress("send email address", "Example User");
        var subject = "Sending with SendGrid is Fun";
        var to = new EmailAddress("To email address", "Example User");
        var plainTextContent = $"Name : aaaa";
        var htmlContent = "<strong>and easy to do anywhere, even with C#</strong>";
        var msg = MailHelper.CreateSingleEmail(from, to, subject, plainTextContent, htmlContent);
         client.SendEmailAsync(msg).Wait();

        int i = 0;