CODEWITHSUNDEEP
c#.netsmtpsmtpclient
Xavier Poinas
Xavier Poinas

Reputation: 19733

SmtpException: The client or server is only configured for e-mail addresses with ASCII local-parts

The SmtpClient.Send() method is throwing this exception when I try to send an email to an address containing an accentuated character (é):

System.Net.Mail.SmtpException: The client or server is only configured for e-mail addresses with ASCII local-parts: lé[email protected].
at System.Net.Mail.MailAddress.GetAddress(Boolean allowUnicode)
at System.Net.Mail.SmtpClient.ValidateUnicodeRequirement(MailMessage...)
at System.Net.Mail.SmtpClient.Send(MailMessage message)

The formulation of the message makes me thing there might be a setting that I can activate to make this work, though I haven't found anything on this subject.

I have tried several SMTP servers, including Gmail. Here are the relevant bits for a repro:

Code

var msg = new MailMessage();
msg.Subject = "Test";
msg.From = new MailAddress("[email protected]");
msg.To.Add(new MailAddress("lé[email protected]"));

new SmtpClient().Send(msg);

app.config

<system.net>
    <mailSettings>
        <smtp from="[email protected]">
            <network host="smtp.gmail.com" port="587" userName="[email protected]" password="password" enableSsl="true" />
        </smtp>
    </mailSettings>
</system.net>

Upvotes: 21

Views: 29535

Answers (4)

Andrew
Andrew

Reputation: 2715

If the DeliveryFormat property of your SmtpClient instance is set to SmtpDeliveryFormat.SevenBit (the default) then you need to make sure your SMTP gateway is replying with SMTPUTF8 when sent EHLO by .NET while it's trying to send the email. SmtpClient uses this to work out if the gateway is able to support UTF8.

According to the source for both .NET Framework 4.5+ and .NET core, the receiving server must support UTF8 and the DeliveryFormat must be set to SmtpDeliveryFormat.International in order to be able to send.

For the latest logic and full details, see IsUnicodeSupported in:

Upvotes: 29

Santhosh N
Santhosh N

Reputation: 82

The below code worked for me.

SmtpClient smtpClient = new SmtpClient(SMTPServer, SMTPPort)
{
    Credentials = new NetworkCredential("SMTPUserName", "SMTPPassword"),
    EnableSsl = true,
    DeliveryFormat = SmtpDeliveryFormat.International,
};

Upvotes: 1

robasta
robasta

Reputation: 4701

Late answer, but, I solved this by specifying encoding like this:

var mailMessage = new MailMessage
            {
               From = new MailAddress("[email protected]", "Test User", Encoding.UTF8)
}

In my case, the server was causing the error.

Upvotes: 2

tsells
tsells

Reputation: 2771

.net only supports ASCII characters. I don't believe it supports extended ASCII characters (which includes the accented e in question).

http://www.asciitable.com/

We ran into the same issues with users trying to use the danish character for a / e.

Upvotes: -7

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