All of a sudden I am getting a large number of "Mail delivery failed" messages from my WordPress installation.
They appear to be the standard emails WordPress sends automatically when a new comment is being posted. But instead of being sent to me, they are being sent back to another email address, but bouncing back because the address cannot be found.
It's as if someone has changed the settings within my site to send email notifications to someone else. The problem continues even if I turn off email notifications.
Can anyone help me find the problem here? Has my site been hacked?