Spam mails send by non-existed mail account

[emre yoruk]

Dear sir,
One of domain hosted in my server send spam mails by non-existed mail accounts. How to set to disable this kind of harmfull settings or softwares?I'm scared to enter my IP address blacklisted. Please let me how to fix this problem?

mrprove@stepgrup.com .. such an e-mail address is non-existed (not registered) in the system, but send lots of spam
owjwgulf@stepgrup.com.. such an e-mail address is non-existed (not registered) in the system, but send lots of spam
xmtrepan@stepgrup.com..such an e-mail address is non-existed (not registered) in the system, but send lots of spam

 

[IgorG]

Hmm... Domain can't send mails by itself. It can be done by owner of domain or by some third-party software.

 

[emre yoruk]

I check it, there is no 3thrd party software. I also scan with anti-virus programs ( Kaspersky). Then I reloaded web files but it doesnt improvement