Undelivered mail messages from Mailer Daemon


The last few days I have been getting messages in my email saying return to sender undelivered mail (maybe not those exact words, but words to that effect). These messages mainly have been coming from plus a few others that are coming from various sources (recipients?) saying they are notifying that there is malware in the email that I have sent and they have blocked it.


I am getting literally hundreds of these every day in my inbox.


I have not sent any email at all to be undelivered and then bounced.


I have not opened any suspect email or clicked a link in any email, except from a trusted source.


I have run a full system scan with my updated and current Norton antivirus and found nothing.


I am a bit of an idiot when it comes to these wizard box computer thingies, so be gentle with me.



What have I done, and what can I do to stop this from happening?

Re: Undelivered mail messages from Mailer Daemon


Probably not a lot. Someone is likely spoofing your address rather than using your account.


Can you make a rule to just delete the emails as they come in? Based on the subject?


Peter Gillespie

Re: Undelivered mail messages from Mailer Daemon




Yeah I already do delete them, it is just that there are hundreds of them every day to just read the 3 or 4 emails that actually mean anything.

Re: Undelivered mail messages from Mailer Daemon

[ Edited ]

You can delete them maually but can you set up a rule to delete them automatically?


If not its one of a multitude of reasons to migrate off a ISP email address. 2FA, spam protection, freedom to leave, etc. 


You can setup a free GMail account today and set it to import all old and new emails automatically. 


Peter Gillespie

Re: Undelivered mail messages from Mailer Daemon


This just happened to me too. When someone replied asking about the email I'd sent I realsied I'd been hacked and somehow emails were being sent from my account to random email addresses that could be trawled online I think. I could see the sent email when I logged into webmail through optus. There were hundreds and hundreds. It also maxxed out my email with these and the bounce backs. I figure there was some problem with Optus (as well, or because of, or that caused this) as the webmail page was also melting down and going offline. I changed my password and deleted all the sent emails and bounce backs. I'll cross my fingers for now. Good luck

Re: Undelivered mail messages from Mailer Daemon


If you can see the sent emails then yess you have been hacked and lucky the hackers didn't change your password.


If you can only see bounce back emails then is likely an email spoof which means your email is safe but known.


Peter Gillespie

Re: Undelivered mail messages from Mailer Daemon


Thanks Peter, but I think you may have missed the part where I said I am an idiot when it comes to all this.


I have no idea what you just said, so can I set up a rule? No. A smarter person maybe, but not me.


Anyway, it never occured to me to check the "sent" folder until after reading the next few replies.


900+ emails sent in the last 3 days, so it appears my account was hacked. 3 days ago I logged into my email to check my payslip using my phone so that is when it would have happened.


I have now changed my password so I hope that fixes it.


Thanks for your help.



undelivered emails


I am receiving an increasing number of undelivered email messages from the Mail Delivery System

How do I solve this problem?


Re: undelivered emails


Some advice on this recent thread: Undelivered mail messages from Mailer Daemon

As this is the same issue, we will merge the two together.

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