I need a specialist for Cleaning my web server

Hello guys.
I have the following issues to my detieated server in leaseweb.

Hello Abuse-Team,

your Server/Customer with the IP: *78.159.98.209* (router.gotham.gr) has attacked one of our servers/partners.
The attackers used the method/service: *ssh* on: *Tue, 08 Feb 2022 01:12:35 +0100*.
The time listed is from the server-time of the Blocklist-user who submitted the report.
The attack was reported to the Blocklist.de-System on: *Tue, 08 Feb 2022 01:12:37 +0100*

So maybe there is a trojan to my deticated server.
I dont know how to clean it !