Status 21.04.2020: eMails von meiner ...@t-online.de-Adresse an mehrere ...@hotmail.de-Adressen werden nicht zugestellt.
Fehlermeldung:
host eur.olc.protection.outlook.com[104.47.13.33]
    said: 550 5.7.1 Unfortunately, messages from [194.25.134.85] weren't sent.
    Please contact your Internet service provider since part of their network
    is on our block list (S3140). You can also refer your provider to
    http://mail.live.com/mail/troubleshooting.aspx#errors.
    [HE1EUR04FT056.eop-eur04.prod.protection.outlook.com] (in reply to MAIL
    FROM command).
Was kann ich tun? Wo liegt der Fehler?

VG HD+