I just came to search the forum to see if I'm the only one having this problem, and I see that I am not! It's a lot more than 4 instances for me though... over just the last few days I've had HUNDREDS of messages flood my account, all returned mail from different places, coming back as undeliverable, as though they were sent from my domain.
This started suddenly, just a few days ago. It's as though someone is sending out SPAM from my domain, using random.names@myacount.com and all the undeliverables are coming back to my default mail account.
I saw the reply that this was probably just a tricky way to get a message into my inbox, but it sure seems like more than that. These are coming from so many different places... and it just started over night.
Does anyone have any ideas??