Leute, das solltet ihr mal dringend reparieren...

Ich habe eine EMail an einen hotmail-Empfänger sowie im CC and einen web.de-Empfänger geschickt.

hotmail hat sich geweigert die Mail anzunehmen (siehe unten), von web.de kam keine Fehlermeldung

This is the mail system at host mailout06.t-online.de.

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

 *****@hotmail.de : host
    eur.olc.protection.outlook.com[104.47.8.33] said: 550 5.7.1 Unfortunately,
    messages from [194.25.134.19] weren't sent. Please contact your Internet
    service provider since part of their network is on our block list (S3140).