Tú@gmail.com is not a valid email address, at least for SMTP. The various SMTP and message format RFCs (821, 822, 2821, 2822, 5321 and 5322) all require that email addresses contain only us-ascii characters. There are extensions such as RFC 2047 and RFC 2231 that specify encoding for non-ascii characters in email message headers, but RFC 2047 at least is clear that email addresses can't be encoded, and in any case, these apply only to headers in message text, not to email addresses in SMTP MAIL FROM and RCPT TO commands. The fact that the invalid email address is reported as "Error: Illegal Email Address: Tú@gmail.com" and not "Error: Illegal Email Address: Tú@gmail.com" is due to overprotecting against XSS attacks resulting of double-escaping of the & character. This is fixed in 2.1.13. I am unable to duplicate "If the email address have words such then mailman spews out 'We've hit a bug' page." even at <http://ngocentre.org.vn/mailman/listinfo/wildtrade>. Please be more specific as to exactly what is entered where to produce this, and if possible provide the traceback from Mailman's error log. -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/781487 Title: Fails to process Vietnamese Characters in email links