Unable to send to from Zoho Mail to Hotmail.

Unable to send to from Zoho Mail to Hotmail.

Hi, I am unable to send a mail from Zoho to Hotmail.  It bounces back as shown below.
That Hotmail address normally receives mails OK. So I believe it's an issue with Zoho.

(Note: I have altered the mail addresses in this post with "xxx", for privacy).

  1. 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.

    xxx@hotmail.com, ERROR CODE :550 - 5.7.1 Unfortunately, messages from [103.163.153.2] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [CO1NAM11FT029.eop-nam11.prod.protection.outlook.com]



    Reporting-MTA: dns; mx.zohomail.jp
    Arrival-Date: Tue, 10 Jan 2023 14:17:53 +0900

    Original-Recipient: rfc822; xxx@hotmail.com
    Final-Recipient: rfc822; xxx@hotmail.com
    Status: 550
    Action: failed
    Last-Attempt-Date: 10 Jan 2023 05:17:58 GMT
    Diagnostic-Code: 5.7.1 Unfortunately, messages from [103.163.153.2] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [CO1NAM11FT029.eop-nam11.prod.protection.outlook.com]


    Received:from mail.zoho.jp by mx.zoho.jp
        with SMTP id 1673327873922425.273392398963; Tue, 10 Jan 2023 14:17:53 +0900 (JST)
    Message-ID:<1859a1d0f61.7690becd1013.2925303433593739485@xxx.com>
    Date:Tue, 10 Jan 2023 14:17:53 +0900
    From:Arka Roy <xxx@xxx.com>
    To:"Arka Roy" <xxx@hotmail.com>
    Subject:Test Zoho to Hotmail
    Content-Type:multipart/alternative;
        boundary="----=_Part_1980_336912633.1673327873889"
    User-Agent:Zoho Mail



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