UTF-8 mail address not working

[VILLAN3LL3]

I'm using fakeSmtp for unit testing in my .Net Core project with random generated test data by Faker.Net.
Sending a mail with characters that are not part of ASCII leads to the following exception:

Message: System.Net.Mail.SmtpException : The client or server is only configured for E-mail addresses with ASCII local-parts: valentina_möcks@krolsussmann.ch.

In my configuration I set the host to localhost, the port to 25 and the DeliveryFormat to SmtpDeliveryFormat.International.

When creating a mailAddress object I use Encoding.Utf8.

How can I use FakeSMTP to send mails with UTF-8 encoded mail addresses? Thank you

[Vest]

Do you have a call stack (of the exception) from the FakeSMTP server? It will probably give us a clue what settings should be changed.
Unfortunately, this project seems dead to me, the owner hasn't accepted PRs since ages :(