@Aneesh

It is Gmail that takes that much time, please contact their support, if you believe it should act faster.

“No identity changes permitted. im2sm50492321pbd.31 – gsmtp” error

This error is generated by the server.

You can login to the server only once. Which means that you need a separate connection for every user you try to login as. Please note that this is not Mail.dll’s limitation nor bug – this is how SMTP protocol, and in fact all mail protocols, work.

Only advice I have for you is to create multiple threads, each with its own Smtp class instance, and send several emails through Gmail simultaneously.

using(Smtp smtp = new Smtp())
{
    smtp.ConnectSSL("smtp.gmail.com");
    for (int i = 0; i < 5; i++)
    {
        smtp.LoginOAUTH2(from, accesstoken);  // this gives an exception 
        SendMessageResult result = smtp.SendMessage(email);
    }
    smtp.Close()
}

Regards,
Aneesh Kumar.

@Aneesh,

Which part takes so long? OAuth2? Are you reusing Smtp object?
Could it be that this is a problem with your network? Gmail server? Gmail is known for enforcing many limits on its users.

I don’t believe that this is the problem with Mail.dll – its speed is up to 230 ms/100 emails (local server). Generally on production servers its much less than 200ms/email (around 20-50ms)

The only “problem” I can see in your code is, that you can use ConnectSSL instead of Connect and StartTLS sequence:

smtp.ConnectSSL("smtp.gmail.com");

using (Smtp smtp = new Smtp())
{
    smtp.Connect("smtp.gmail.com", 587);                 
    smtp.StartTLS();
    smtp.LoginOAUTH2(from, accessToken);
    SendMessageResult result = smtp.SendMessage(email);
    smtp.Close();
}

It takes 6 to 7 second to send E-mail which is a worry. Could you let us know what could be the reason. If we purchase will this speed be better.

Regards,
Aneesh Kumar

@Aneesh,

1. MailBuilder class is not indented to be serialized, or transferred between client and server.
2. Classes, such as ContentType, MimeType can not have default constructor, so XML serialization won’t work for them.
3. There are properties with type of interface (such as IList) on MailBuilder, which will also prevent serialization.
4. It is not possible (not secure) to transfer certificate classes, used for signing or encrypting emails, between two machines.

The bottom line is: use MailBuilder to create or parse emails, but don’t use it as a data transfer object (DTO) – it was not designed for this purpose.

Any help is appreciated

builder.Html = sRTF_To_HTML(RichTextBox1.Rtf);

and it worked like a charm! Thanks again.

@lana

1.
[from msdn]
The Text property does not return any information about the formatting applied to the contents of the RichTextBox.
To get the rich text formatting (RTF) codes, use the Rtf property.

2.
Are you sure that your email client supports rtf content?
What email client are you using?

Dim rtf = New MimeFactory().CreateMimeText()
rtf.ContentType = New ContentType(MimeType.Text, MimeSubtype.Rtf)
rtf.Text = RichTextBox1.Text
builder.AddAlternative(rtf)

Dim email As IMail = builder.Create()

but it did not work for me, it just attached a plane text file ‘noname’ to the email. I must be doing it wrong…

@Lana

You can use AddAlternative method:

MailBuilder builder = new MailBuilder();
builder.Text = "plain text";
var rtf = new MimeFactory().CreateMimeText();
rtf.ContentType = new ContentType(MimeType.Text, MimeSubtype.Rtf);
rtf.Text = @"{rtf1ansideff0
{colortbl;red0green0blue0;red255green0blue0;}
This line is the default colorline
cf2
This line is redline
cf1
This line is the default color
}";
builder.AddAlternative(rtf);
IMail mail = builder.Create();

Please note that not all email clients support and are able to display RTF formatted email.