I received 2 mailer-daemon failure notice for emails i know I didn't sent to recipients I don't recognize. I noticed them after havimg to relog into yahoo on my phone and i never log off. I checked recent activity under account info and it only showed my phone and didn't even show the 2 tiles I logged in on a library computer this past month. Was i hacked? Is there a way to find out when and where those emails were sent?
You were not hacked. The spammers manually enter your address in the REPLY in order to fool the spam filters. The recipient can check the Header to find out who really sent them. i don't know if you can do that with a Daemon message.