These instructions that you followed are for a manual installation
I suggest that you follow the apt-get installation method: https://docs.openhab.org/installation/linux.html#package-repository-installation
(in the apt-get case, the openhab2.service file is created for you)
Also: How to use code fences
(and: it’s better to open up a new thread since this one is marked as solved)
hmmm… permissions maybe?