At this stage…
I would suggest,
-
Remove the network Thing (wait for openHAB2 to fully remove it)
-
restart the PI
-
Try to connect to the PI with VelbusLink
If that is good
- Add a Velbus Network Bridge
You might want to look at this topic, for guidance on removing any artifacts of the Velbus binding, then ensure you have the very latest version.
https://forumtest.velbus.eu/t/velbus-binding-for-openhab/14992/165
Scroll through that entire thread, there is lots of information in there.