Outgoing Email Are bing Generated Without any mail server

Dear Sir,

We have noticed a significant increase of outgoing connections from your server with IP 15, (D0000000 Websites). The level of SMTP traffic on port 25/tcp is unusually high and at this pace you will hit the limit soon and all connections on this port will be blocked until the next day.
We do this to protect the reputation of our network and to make sure that your Ip’s, and all our customers, will not be blacklisted.

The most common explanation of such a spike in outgoing connections is that your server was hacked. If this is the case, we recommend reinstalling your server from scratch.
If these connections are initiated by you on purpose, please reply to this email and let us know what the expected traffic volume is and we will adjust the limits accordingly.

I have received this email from my server but i don’t have the email that they are referring on my server how do i limit or block those outgoing emails

I am also getting the same issue .

Looking for a solution . It started happening with my server from last 10 days.

Kindly anyone help.

You should block port 25 in your firewall.

not helpful. I can see that there are email getting send from a webmail which is of one of my domain which i deleted from cyberpanel but still mails are getting send and i cant do anything. And i havent created that mail and i am unaware about it. but still mails are getting send from it i have seen the reports in mailwatch mailscanner.