Allright, i think i fixed this. It seems i was missing some kernel sources/headers. I found this KB https://www.veeam.com/kb2259
I ran the following command to fix it:
sudo apt-get install linux-headers-$(uname -r)
Then i ran:
sudo dkms build -m veeamsnap -v 18.104.22.1684
sudo dkms install -m veeamsnap -v 22.214.171.1244
But i dont think i even needed to run the 2 last command, as they stated it was already build / installed.
Oh almost forgot, -Thank you for your help!!