Permanent SMTP error: permanent 5.5.2

Hallo,
auf einem Iphone funktionierendes Profil wurde mit der klassischen Methode zu einem Windows 11 Desktop übertragen.
Deltachat lässt sich dort öffnen, aber es werden keine Nachrichten versendet oder empfangen.
Es erscheint die Fehlermeldung:
“Error: Permanent SMTP error: permanent: 5.5.2
<[2a02:908:1e4:b920::d250]>Helo command rejected: invalid ip address
Message-ID:; Mr. TdWT4SU6MJ-.PcnhKe2IraN@localhost
No hop Info”
Kann jemand helfen?


Dirk

Error “invalid ip address” is generated by Postfix check “reject_invalid_helo_hostname”. Delta Chat sends [127.0.0.1] as the HELO hostname which passes this check, so this cannot be a rejection from Postfix smtpd that Delta Chat connects to:

Probably Postfix fails to send message further.

Many thanks for your answer.
Curiosly the error exits since adding a new profile with the team managed mail server nine.testrun.org.
A formerly created profile on the same PC with mail server mail.de works fine. So it looks like the new profile or the mailserver is reasonable for the error message.
But I do not know a way to fix.