Emailing certificates gets rejected as spam

[mbernasocchi]

This is the mail system at host kartoza.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<edited.email@ne.ch>: host mx1.ne.ch[148.196.30.21] said: 550 High
    probability of spam (in reply to end of DATA command)

Reporting-MTA: dns; kartoza.com
X-Postfix-Queue-ID: 816A559B
X-Postfix-Sender: rfc822; marco@opengis.ch
Arrival-Date: Thu,  8 Feb 2018 12:04:30 +0000 (UTC)

Final-Recipient: rfc822; edited.email@ne.ch
Original-Recipient: rfc822;edited.email@ne.ch
Action: failed
Status: 5.0.0
Remote-MTA: dns; mx1.ne.ch
Diagnostic-Code: smtp; 550 High probability of spam

Certificate from Python programming in QGIS (PyQGIS) Course.eml
Subject: 
Certificate from Python programming in QGIS (PyQGIS) Course
From: 
marco@opengis.ch
Date: 
08.02.2018 13:04
To: 
edited.email@ne.ch

Dear XXXXXXXXX,

Congratulations!
Your certificate from the following course has been issued.

Course type: Python programming in QGIS (PyQGIS)
Course date: 13 November 2017 to 14 November 2017
Training center: "On site training"
Certifying organisation: OPENGIS.ch GmbH

You may print the certificate by visiting:
http://changelog.qgis.org/en/qgis/certifyingorganisation/qgis-opengisch-gmbh/course/qgis_python-programming-qgis-pyqgis_2017-11-13-2017-11-14-2/print/131/

Sincerely,
Marco Bernasocchi

[mbernasocchi]

got this from 4 of 10 emails (all 4 at the same domain)

[timlinux]

Hmm maybe one solution for this would be to give the course convenor a message that he can send from his own mailbox...otherwise I need to think how we can manage this....