Blocked outbound emails

Hello, 

Can you provide the full bounceback so I can get this reported?

Here are two examples with the email addresses omitted. Oddly some hotmail emails do get delivered.

hotmail;

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 hotmail-com.olc.protection.outlook.com [104.47.73.161]

    SMTP error from remote mail server after pipelined end of data:

    550 5.7.1 Unfortunately, messages from [66.96.187.6] 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. [MW2NAM04FT042.eop-NAM04.prod.protection.outlook.com 2023-02-23T16:42:50.964Z 08DB15A90517548C]

rr.com

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 pkvw-mx.msg.pkvw.co.charter.net [47.43.26.7]

    SMTP error from remote mail server after RCPT TO:<>:

    550 5.1.1 <> recipient rejected