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Author thunderk
Recipients matrixise, thunderk
Date 2018-01-30.15:47:51
SpamBayes Score -1.0
Marked as misclassified Yes
Message-id <>
Sure :

#coding: utf-8
import email.utils
from email.message import EmailMessage
from smtplib import SMTP
m = EmailMessage()
m['From'] = email.utils.formataddr(("Michaël", ""))
m['To'] = email.utils.formataddr(("René", ""))
with SMTP('localhost') as smtp:

On a server without SMTPUTF8, this outputs:

16:39:26.351302 send: 'ehlo localhost\r\n'
16:39:26.351391 reply: b'250-localhost\r\n'
16:39:26.351414 reply: b'250-PIPELINING\r\n'
16:39:26.351427 reply: b'250-SIZE 10240000\r\n'
16:39:26.351437 reply: b'250-VRFY\r\n'
16:39:26.351448 reply: b'250-ETRN\r\n'
16:39:26.351458 reply: b'250-ENHANCEDSTATUSCODES\r\n'
16:39:26.351468 reply: b'250-8BITMIME\r\n'
16:39:26.351477 reply: b'250 DSN\r\n'
16:39:26.351490 reply: retcode (250); Msg: b'localhost\nPIPELINING\nSIZE 10240000\nVRFY\nETRN\nENHANCEDSTATUSCODES\n8BITMIME\nDSN'
16:39:26.351832 send: 'QUIT\r\n'
16:39:26.351901 reply: b'221 2.0.0 Bye\r\n'
16:39:26.351923 reply: retcode (221); Msg: b'2.0.0 Bye'
Traceback (most recent call last):
  File "/usr/lib/python3.5/", line 943, in send_message
    ''.join([from_addr, *to_addrs]).encode('ascii')
UnicodeEncodeError: 'ascii' codec can't encode character '\xeb' in position 5: ordinal not in range(128)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "", line 12, in <module>
  File "/usr/lib/python3.5/", line 947, in send_message
    "One or more source or delivery addresses require"
smtplib.SMTPNotSupportedError: One or more source or delivery addresses require internationalized email support, but the server does not advertise the required SMTPUTF8 capability

With removing the accented character in the sender name :
m['From'] = email.utils.formataddr(("Michael", ""))

It works :

16:42:49.882358 send: 'ehlo localhost\r\n'
16:42:49.882437 reply: b'250-localhost\r\n'
16:42:49.882460 reply: b'250-PIPELINING\r\n'
16:42:49.882474 reply: b'250-SIZE 10240000\r\n'
16:42:49.882486 reply: b'250-VRFY\r\n'
16:42:49.882498 reply: b'250-ETRN\r\n'
16:42:49.882509 reply: b'250-ENHANCEDSTATUSCODES\r\n'
16:42:49.882520 reply: b'250-8BITMIME\r\n'
16:42:49.882530 reply: b'250 DSN\r\n'
16:42:49.882543 reply: retcode (250); Msg: b'localhost\nPIPELINING\nSIZE 10240000\nVRFY\nETRN\nENHANCEDSTATUSCODES\n8BITMIME\nDSN'
16:42:49.883439 send: 'mail FROM:<> size=86\r\n'
16:42:49.886567 reply: b'250 2.1.0 Ok\r\n'
16:42:49.886603 reply: retcode (250); Msg: b'2.1.0 Ok'
16:42:49.886666 send: 'rcpt TO:<>\r\n'
16:42:49.889642 reply: b'250 2.1.5 Ok\r\n'
16:42:49.889676 reply: retcode (250); Msg: b'2.1.5 Ok'
16:42:49.889694 send: 'data\r\n'
16:42:49.889769 reply: b'354 End data with <CR><LF>.<CR><LF>\r\n'
16:42:49.889827 reply: retcode (354); Msg: b'End data with <CR><LF>.<CR><LF>'
16:42:49.889843 data: (354, b'End data with <CR><LF>.<CR><LF>')
16:42:49.889939 send: b'From: Michael <>\r\nTo: =?utf-8?q?Ren=C3=A9?= <>\r\n\r\n.\r\n'
16:42:49.892726 reply: b'250 2.0.0 Ok: queued as D92C540105\r\n'
16:42:49.892752 reply: retcode (250); Msg: b'2.0.0 Ok: queued as D92C540105'
16:42:49.892764 data: (250, b'2.0.0 Ok: queued as D92C540105')
16:42:49.892786 send: 'QUIT\r\n'
16:42:49.892862 reply: b'221 2.0.0 Bye\r\n'
16:42:49.892896 reply: retcode (221); Msg: b'2.0.0 Bye'

As you can see, the sender and recipients names are not sent in SMTP command, except in the MIME body, so they should not be used to determine whether SMTPUTF8 is required or not.
Date User Action Args
2018-01-30 15:47:51thunderksetrecipients: + thunderk, matrixise
2018-01-30 15:47:51thunderksetmessageid: <>
2018-01-30 15:47:51thunderklinkissue32727 messages
2018-01-30 15:47:51thunderkcreate