Jeffrey Stedfast

I might have to add an SmtpServiceNotAuthenticatedException to add those properties because they won't map as easily for POP3 and IMAP.

Question: When you get `MailKit.Net.Smtp.SmtpProtocolException: The SMTP server has unexpectedly disconnected: 2.1.0 OK xxxxxxxxxxxxxxxxxxxxxxxxxxxxx - gsmtp`, is it when calling a NoOpAsync() or something?

That ... doesn't make sense unless there's a bug in the SendAsync logic. I don't understand how that could happen :( That response text suggests that this is happening *after*...

No, it would only come as a response to sending the message content. That `xxxxxxx...` is a "tracking id". Do you have a `MessageSent` event handler? If it throws an...

Actually, my analysis is wrong I think, because it only calls `RSET` if it gets an `SmtpCommandException` or a `ServiceNotAuthenticatedException`, but then it will *throw* the original exception (or should)....

> Most of the SmtpProtocolExceptions we're getting are with 4.x.x and 5.x.x. That's what I would expect and gives me *some* measure of relief :-) > The 2.x.x SmtpProtocolException are...

> because I'm assuming you wouldn't generally detect the disconnect until the read of the next command after a DATA/BDAT response has already been processed? Correct, that is the way...

Okay, that should improve the situation a bit. Hopefully.

Just checked out v4.3.0 and indeed, the old 4.3.0 code used to swallow RSET exceptions.

> So, it seems in most cases MailKit will know that the server disconnected due to the attempt to RSET after a bad DATA/BDAT 4xx/5xx response or bad MAIL FROM/RCPT...