What is the name of the domain?
তৌহিদুর.বাংলা
What is the issue you’re encountering
Cloudflare Email Routing is rejecting valid UTF8 email addresses
What are the steps to reproduce the issue?
Try to email ক্লাউডফ্লেয়ার@তৌহিদুর.বাংলা
When your (e.g. sender’s) mail server establishes connections to other mail servers, the other mail servers will demonstrate their capabilities:
Google (Gmail) does for example announce these:
$ telnet gmail-smtp-in.l.google.com. 25
Trying 2a00:1450:4025:c03::1b...
Connected to gmail-smtp-in.l.google.com.
Escape character is '^]'.
220 mx.google.com ESMTP xxx - gsmtp
EHLO mail.example.com
250-mx.google.com at your service, [xxx]
250-SIZE 157286400
250-8BITMIME
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-CHUNKING
250 SMTPUTF8
QUIT
221 2.0.0 closing connection xxx - gsmtp
Connection closed by foreign host.
250-SIZE 157286400 does for example say that the total size of the message cannot be above 157286400 bytes.
250 SMTPUTF8 does for example indicate that Google (Gmail) accepts SMTPUTF8.
However, - when connecting to Cloudflare Email Routing:
$ telnet route1.mx.cloudflare.net 25
Trying 2606:4700:f5::c...
Connected to route1.mx.cloudflare.net.
Escape character is '^]'.
220 mx.cloudflare.net Cloudflare Email ESMTP Service ready
EHLO mail.example.com
250-mx.cloudflare.net greets mail.example.com
250-STARTTLS
250-8BITMIME
250 ENHANCEDSTATUSCODES
QUIT
221 2.0.0 mx.cloudflare.net Cloudflare Email ESMTP Service closing transmission channel
Connection closed by foreign host.
Cloudflare Email Routing does NOT indicate that that it’s capabilities include SMTPUTF8.
No, Cloudflare is NOT rejecting the message.
Your (sender’s) mail server established a connection to Cloudflare Email Routing, and found that Cloudflare didn’t signal the SMTPUTF8 capability, and therefore, your (sender’s) mail server gave up on continuing with the delivery, because the message required that capability.
A server that does not indicate SMTPUTF8 capabilities does not support these special characters in the local part (the part before @).
However, for the domain part, there is the alternative with Punycode encoding, e.g. “xn--45be4a8a4an7e.xn--54b7fta0cc”.
If you’re looking for an alternative, -
One potential alternative is to avoid SMTPUTF8 characters in the local part.
“example@তৌহিদুর.বাংলা” should be working fine, due to the possibility for Punycode encoding of the domain name.
It is (unfortunately) still quite much a foot gun to be depending on SMTPUTF8 characters in the local part, even in 2024.
Switched to another email routing provider. One of the only reason I bought a dot Bangla domain is to use fully Bangla email addresses. So, not having this is very sad to me.
I don’t get it. Why do they support internationalized domain names but not addresses? Sigh. This should be available by default.
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