Help with Network interface, openhab & pivccu

  • Platform information:
    • Hardware: rspi 3
    • OS: openhabian
    • openHAB version:2.2

Hi Everyone!
i tried to run pivccu & openhab 2 together on one rspi3. Openhabian runs fine and i started to install pivccu
with this guide:

It already runs but now i cant access via ssh or browser, no items could be switched.
I can access directly to the pi via keyboard

i think this step is the problem:

sudo apt remove dhcpcd5
sudo apt install bridge-utils
sudo bash -c 'cat << EOT > /etc/network/interfaces
source-directory /etc/network/interfaces.d

auto lo
iface lo inet loopback

iface eth0 inet manual

auto br0
iface br0 inet dhcp
bridge_ports eth0

i checked if eth0 is correct and then i done this and after that i cant access
i cant undo it… could someone help me with the correct steps…
thx a lot!!