SMTP Error with freenet mail

Help
1

Hi,
there is an error setting up the freenet.de mail.
Mail Name, Password, Server and Port is correct.
IMAP is ok - SMTP mistake
Where is the mistake ?
Thanks for your help

Logfile
----------IMAP----------
connect mailcore::IMAPSession:0098F900

  • OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
    ssl connect mx.freenet.de 993 2
    OpenSSL version: OpenSSL 1.1.0f 25 May 2017
    connect ok
    login
    1 LOGIN “x__xxxxx@freenet.de” *********
    1 OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY PREVIEW=FUZZY PREVIEW STATUS=SIZE SAVEDATE LITERAL+ NOTIFY METADATA SPECIAL-USE QUOTA] Logged in
    2 ENABLE QRESYNC
  • ENABLED QRESYNC
    2 OK Enabled (0.001 + 0.000 secs).
    3 NAMESPACE
  • NAMESPACE ((“INBOX.” “.”)) NIL NIL
    3 OK Namespace completed (0.001 + 0.000 secs).
    login ok
    4 LIST “INBOX.” “*”
  • LIST (\HasNoChildren \UnMarked \Junk) “.” INBOX.virenverdacht
  • LIST (\HasNoChildren \UnMarked) “.” INBOX.testmail
  • LIST (\HasNoChildren \UnMarked \Junk) “.” INBOX.spamverdacht
  • LIST (\HasNoChildren \UnMarked \Sent) “.” INBOX.sent
  • LIST (\HasNoChildren \UnMarked \Drafts) “.” INBOX.drafts
  • LIST (\HasNoChildren \UnMarked) “.” INBOX.Trash
    4 OK List completed (0.040 + 0.000 + 0.039 secs).
    5 LIST “” “INBOX”
  • LIST (\HasChildren) “.” INBOX
    5 OK List completed (0.001 + 0.000 secs).

----------SMTP----------
connect mx.freenet.de 587
220 sub1.freenet.de ESMTP Exim 4.94.2 Mon, 17 Apr 2023 17:39:01 +0200
init
EHLO xxxxx_PC
501 Syntactically invalid EHLO argument(s)
HELO xxxxx_PC
501 Syntactically invalid HELO argument(s)
QUIT

SASL_PATH:

SMTP Last Response Code: 501
SMTP Last Response: Syntactically invalid HELO argument(s)

mailsmtp Last Error Code: 1
mailsmtp Last Error Explanation: MAILSMTP_ERROR_UNEXPECTED_CODE
mailsmtp Last Error Location: 2
mailsmtp Last Auth Type: 0

2

Your log shows the exact cause: it’s the name of your computer, not your freenet settings:

EHLO xxxxx_PC
501 Syntactically invalid EHLO argument(s)

When Mailspring connects to an SMTP server it identifies itself with your machine’s hostname. freenet’s Exim server strictly follows the RFC, and an underscore isn’t allowed in a hostname, so it refuses the greeting before you ever get to log in. (IMAP doesn’t do this handshake, which is why that half worked.) Mailspring already replaces spaces in hostnames but not underscores — I’ve noted that as a bug to fix.

On your end, rename the PC so the name only contains letters, digits, and hyphens (on Windows: Settings > System > About > “Rename this PC”), reboot, then connect the account again.