by Santeri » 2019-12-11 09:07
I made a web app using
internationalized domain name (IDN). The domain name is
lisäämyyntiä.com which is in
punycode format
https://www.xn--lismyynti-x2aag.com/. When I send email to the IDN, Gmail is giving me error messages claiming that the receiving email server is
misconfigured.
Message not delivered
Your message couldn't be delivered to test@lisäämyyntiä.com because the remote server is misconfigured. See the technical details below for more information.
Same errors happen with or without punycode. Here are the specific, likely bogus Gmail error messages:
550 Please turn on SMTP Authentication in your mail client. mail-ot1-f47.google.com [209.85.210.47]:46638 is not permitted to relay through this server without authentication.
IDNs are messing up Gmail. Other email clients don't give errors when sending emails to punycoded IDN:s. Also the email server works fine and relays, bounces and accepts email from Gmail to all non-IDN-domain without any problems.

I reported this issue to Gmail, but as they don't have a proper error reporting tool, I don't really expect them to do anything to fix this.
I made a web app using [xurl=https://en.wikipedia.org/wiki/Internationalized_domain_name]internationalized domain name[/xurl] (IDN). The domain name is [xurl=https://www.lisäämyyntiä.com/]lisäämyyntiä.com[/xurl] which is in [xurl=https://en.wikipedia.org/wiki/Punycode]punycode[/xurl] format [xurl=https://www.xn--lismyynti-x2aag.com/]https://www.xn--lismyynti-x2aag.com/[/xurl]. When I send email to the IDN, Gmail is giving me error messages claiming that the receiving email server is [b]misconfigured[/b].
[quote]Message not delivered
Your message couldn't be delivered to test@lisäämyyntiä.com because the remote server is misconfigured. See the technical details below for more information. [/quote]
Same errors happen with or without punycode. Here are the specific, likely bogus Gmail error messages:
[quote]550 5.1.1 <test@xn--lismyynti-x2aag.com> Recipient not found. <http://x.co/irbounce>[/quote]
[quote]550 Please turn on SMTP Authentication in your mail client. mail-ot1-f47.google.com [209.85.210.47]:46638 is not permitted to relay through this server without authentication.[/quote]
IDNs are messing up Gmail. Other email clients don't give errors when sending emails to punycoded IDN:s. Also the email server works fine and relays, bounces and accepts email from Gmail to all non-IDN-domain without any problems.
[center][img]https://i.ibb.co/mtKK5Hb/gmail-error-bounce.png[/img][/center]
[center][img]https://i.ibb.co/NxKmpYV/gmail-error.png[/img][/center]
I reported this issue to Gmail, but as they don't have a proper error reporting tool, I don't really expect them to do anything to fix this.