After VM was used to send large amount of spam (open relay, don't know exactly how much cause maillog was 750Mb), I had to do something urgently. Decidet to backup all websites via virtualmin backup, send them to new virtualmin VM with different IP and on different server. Changed nameservers and all worked like a charm for less than a day. But, after that, mail can be received, but can't be send. Maillog looks like I still got large number of spam, which is now refused, cause of milter, don't know if it's somehow connected, so better to say: main.cf looks same like files on other VMs, which can send email: If someone can help, I would really appreciate, cause I'm tired after 2 days of trying to fix this, and I'm running out of time.