Does such a message mean that rejections(bouncies) are set to correct?

Topic: Delivery Status Notification (Failure) //
But this message is only in my S3 email redirection bucket and it doesn’t appear in the bounce tab of the forum administration panel.

from### MAILER-DAEMON@eu-west-1.amazonses.com

An error occurred while trying to deliver the mail to the following recipients:
[therisnobody@nodomainlikeithere8822.com](mailto:therisnobody@nodomainlikeithere8822.com)

---------- Forwarded message ----------
From: new forum <noreply@domain.com>
To: [therisnobody@nodomainlikeithere8822.com](mailto:therisnobody@nodomainlikeithere8822.com)
Cc: 
Bcc: 
Date: Wed, 17 Apr 2019 10:39:46 +0000
Subject: [new forum] Confirm your new account

Welcome to new forum!

Click the following link to confirm and activate your new account:
https://domain.com/u/activate-account/914ee834cd7dbe9eed22da3b49aec11e

If the above link is not clickable, try copying and pasting it into the address bar of your web browser.

Is it just one aspect that everything is ok or there are other things that can be set up? How to check if something else needs to be done?

Generally asking for the following reasons

-I wouldn’t want my messages to be considered spam
-Does not want to lose the reputation of the domain etc. etc.
-Does not want someone to massively create fake accounts and increase artificial traffic.
-I do not want anyone to give mass emails for registration and thus increase the rejection(bounce) rate

and general last aspect somehow related (but only a little bit).
How to get good guard against ddos attacks, etc.