I have been reseiving this type of returned emails as not delivered, i have never sent emails to the addresses must be scams how can you stop them from happening.
This is the mail system at host mail110.syd.optusnet.com.au.
I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can delete your own text from the attached returned message.
The mail system
<firstname.lastname@example.org>: host mx.optimum.net[188.8.131.52] said: 554 5.7.1
Spam detected by content scanner. Message rejected. (in reply to end of
@blob, you could try one of the methods below:
What do if you've receievd a spam or phishing email:
You can report scams, phishing attempts or other hoaxes to the ACCC's Scamwatch website. Alternatively, if someone is phishing for your Optus details via email or a malicious link, you can let us know by forwarding the email and its headers to email@example.com