SPAM Problem

[mhsn1985]

Hello and good day,

I recently installed MailEnable and started all the services to be able to use emails from my company domain. Everything was running well for a few days until today when the "Bad Mail" section of the management console was filled with more than 100 thousand entries (attachment 1) and I was listed in many spamlists!
I have been googling for more than 8 hours now and can't find a solution! It seems a "postmaster" mailbox on my server is being used to relay emails, but I can't find this mailbox anywhere! I activated the spamlists protection in my settings and went through all the settings to see what I can do about this, but just minutes after re-enabling my services, the spammers rushed in again!

Here is a few lines from my SMTP log:

07/19/22 13:57:58 SMTP-OU 24191610EB2D44438386F718EF6F4029.MAI 1368 194.153.145.214 QUIT QUIT - 6 0 postmaster YOUR FUND NOTIFICATION CODE(185.229)
07/19/22 13:57:58 SMTP-OU 24194C8103074F929BCC3AF07E03DDBA.MAI 1044 194.153.145.214 CONN 421 4.7.0 pmx.abv.bg Error: too many connections from 185.94.97.229 0 69 postmaster YOUR FUND NOTIFICATION CODE(185.229)
07/19/22 13:57:58 SMTP-OU 24194C8103074F929BCC3AF07E03DDBA.MAI 1044 194.153.145.214 QUIT QUIT - 6 0 postmaster YOUR FUND NOTIFICATION CODE(185.229)
07/19/22 13:57:58 SMTP-OU 241A4CC2416F4C4A8ED4EE1BE6116CB5.MAI 1812 194.153.145.214 CONN 421 4.7.0 pmx.abv.bg Error: too many connections from 185.94.97.229 0 69 postmaster YOUR FUND NOTIFICATION CODE(185.229)
07/19/22 13:57:58 SMTP-OU 241A4CC2416F4C4A8ED4EE1BE6116CB5.MAI 1812 194.153.145.214 QUIT QUIT - 6 0 postmaster YOUR FUND NOTIFICATION CODE(185.229)
07/19/22 13:57:58 SMTP-OU 241AA54772F94A6E958C42E328A233EE.MAI 900 194.153.145.214 CONN 421 4.7.0 pmx.abv.bg Error: too many connections from 185.94.97.229 0 69 postmaster YOUR FUND NOTIFICATION CODE(185.229)
07/19/22 13:57:58 SMTP-OU 241AA54772F94A6E958C42E328A233EE.MAI 900 194.153.145.214 QUIT QUIT - 6 0 postmaster YOUR FUND NOTIFICATION CODE(185.229)

Last action I took was creating a mail address "Postmaster" and setting a strong password for it. But it still didn't help.

I am in desperate need for your help.

Running version 10.11

[MailEnable-Ian]

Hi,

The first step is to upgrade MailEnable to version 10.40 as 10.11 is outdated and there are security patches that you need to apply.

Review the following article to assist with the upgrade: https://www.mailenable.com/kb/content/article.asp?ID=ME020040

Once you have upgraded review the articles to assist in diagnosing the server abuse:

https://www.mailenable.com/kb/content/article.asp?ID=me020339
https://www.mailenable.com/kb/content/article.asp?ID=me020280