Why am I getting bouncebacks for messages I didn't send?
If you are receiving a large number of replies or bouncebacks for emails that you didn't send, or from email addresses that show your domain but don't exist, you may have been spammed.
There's a spoofing technique where a spammer sends huge volumes of email messages that appear to be from you or someone other than the actual source. Spammers often use a random address in their spam list as the From address to disguise the true source.
Here are some ways you can protect yourself and your email account from being spammed: