Heh. According to Microsoft, there is no problem.
"Thanks for your patience while we investigated your request.
Below your IP address(es) and their status(es) are listed.
74.208.43.115;
Nothing was detected to prevent your mail from reaching Outlook.com customers. Please follow the instructions below."
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Their own mail servers disagree.
Feb 16 12:02:43 HOSTNAME-REDACTED postfix/smtp[10448]: E38BE2C5B2: to=<REDACTEDq@outlook.com>, relay=outlook-com.olc.protection.outlook.com[52.101.11.4]:25, delay=0.33, delays=0.12/0/0.15/0.05, dsn=5.7.1, status=bounced (host outlook-com.olc.protection.outlook.com[52.101.11.4] said: 550 5.7.1 Unfortunately, messages from [74.208.43.115] 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. [SN1PEPF0002529E.namprd05.prod.outlook.com 2024-02-16T17:02:43.190Z 08DC2C3D15CBFFA0] (in reply to MAIL FROM command))