Hello @Robotas and welcome to the community.
If you are using Contabo’s pre-installed Webmin / Virtualmin then it won’t work. This is a known problem with Contabo.
See Error installing in CentOS VPS on Contabo - #7 by calport
The best way forward for those who use Contabo’s pre-installed Webmin / Virtualmin is to kill that VPS, spin up a new one with just the OS installed and then install Virtualmin using the instructions at the official documentation page: https://www.virtualmin.com/automated/