De: Mail Delivery System <Mailer-Daemon@XXXXX>
Enviada: 30 de abril de 2020 17:09
Assunto: Mail delivery failed: returning message to sender
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:
host outlook-com.olc.protection.outlook.com [XXXXXX]
SMTP error from remote mail server after pipelined MAIL FROM:<geral@XXXXXXX> SIZE=8981:
550 5.7.1 Unfortunately, messages from [XXXXXX] 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.
Fazem ideia do que será esse? :\