I already thought, that it must have something to do with the image, which olimex offers on there website.
Don't understand, why they offer such out of date image.
Support did not help me with this problem.
So should I just install the image for the lime2-server from here? https://www.armbian.com/olimex-lime-2-emmc/
But just the non eMMC version, because I run it on the SSD.