Problém s odesílanou poštou - rozesílání jídelníčků

Začaly se vracet chybové hlášky s pokusem o doručení na mailové servery hostované na WEDOS:

Od: **Mail Delivery System** <[](>
Date: čt 1. 9. 2022 v 9:12
Subject: Undelivered Mail Returned to Sender
To: <[](>

This is the mail system at host mx1.

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

<[](>: host []([] said: 504 5.5.2
<mx1>: Helo command rejected: need fully-qualified hostname (in reply to
RCPT TO command)

Už by to mělo fungovat.