If you setup OpenVPN to be in bridge (layer2) mode instead using NAT/routing (layer3) and then restart the server to make the change effective, you probably noticed the following error message on the Status Overview page repeatedly :
service failed to start due to unresolved dependencies: set([‘bridge’])
This is because there is no existing bridge name to join specified here :
Join pre-existing bridge (optional)
Even if it’s written as “optional”, the server will fail to start until you specified one. You actually need to enter the bridge interface name there and restart the server again.