System messages 4000 times


my first thread on this forum.
We’ve been using Directadmin for a while now and I often use the forums for research.
Now I’ve got a problem but I’m unable to find it anywhere on the forum, So I hope someone can help me.

A user is frequently receiving system messages, but last week Directadmin started to multiply them by thousands.
The message system shows the same message like 4000 times.
That’s not the big issue though, the issue is that we receive those message by e-mail on 2 e-mail addresses.
So that creates a lot of outgoing email which might be bad for our IP reputation since we’re using e-mail on another e-mail server.

What could be the probleem or where should I start looking?
I appreciate any help!

Thank you.