Asp.net c# - Sending email with french characters in ToAddress

My requirement is :- i need to send a email which contains "To Address" in french characters.
for eg : éric@domain.com

I am getting the following error message:
"The client or server is only configured for E-mail addresses with ASCII local-parts: éric@domain.com."

After googling for a solution, I found out that you should set the DeliveryFormat to International.

smtpClient.DeliveryFormat = SmtpDeliveryFormat.International;

However, the error seems to be pesisting. could you please suggest me a solution for this.

Thanks in advance,
Prasanth

Are you getting that error message from your mail server, or from the mail server that hosts the email for domain.com?

Hi,
Thanks for the reply, I checked with smtp.gmail.com as host, then it seems to be working. but the same code is not working with our server. May i know reason and how to resolve it.

Thanks in Advance.

That's good, at least it's possible it will work sometimes if the recipient mail server allows it. The trouble is that not all mail servers are going to support email addresses with those types of characters. A lot of work has gone on in recent years to make international domain names work for email and DNS etc. If you really want it to work for your preferred smtp server, I'd check with the support for that mail server. Depending on which mail server they're running, maybe there is an option they can turn on or a patch they can install to support your requirements. If they're able to do that, please let everyone know which MTA and solution was used to get this working for you.