CentOS system emails fail

Dan asked:

The system emails on my CentOS server do not send, they always seem to fail so I’m not alerted to errors or vital notifications.

The settings seem to be correct but there are a few blank entries in the messages that fail, you can see them in the following screenshot:

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My answer:

Hotmail says:

550 SC-001 Mail rejected by Hotmail for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.

To find out anything more, you’ll need to submit a support request to Hotmail.

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