Licensing - no network connection - when OpenVPN in use

Two of our developers work on a remote project and have to connact via OpenVPN client to a distant network. Everything was working when they’ve been using 2017.1 but after they updated to 2017.3 in the last days the licensing module complains with a “no network connection” error.

When they disconnect the VPN connection and work in our local network the error doesn’t appear.
I already contacted the other site’s administrator but he says they didn’t change anything and do not block things.

Could it be that the licensing connection method changed after 2017.1 and is using different ports/servers/protocols?
Is it possible to turn on an licensing debug log to see what “network connection” issues appear in detail?

Also experiencing issues after updating to Unity 2017.3, it’s getting stuck in infinite loops between asking for a login and saying there’s no connection or just saying there’s no connection. Works when VPN is disconnected. Something changed and it’s broken.

Our developers mentioned that in-game network connections (e.g. for http(s) requests) don’t work properly while running a project inside the Unity IDE AND when the vpn-client is active.
In opposite when the game is exported to an .exe networking via vpn works again.

It seems like the IDE in 2017.3 is using the same network-layer for projects & licensing. They both have the same issues with VPN.

My guess is that they probably select the wrong adapter/outgoing ip when starting network-connections. It feels like they always take the first available adapter regardless if it’s currently active or not. During VPN sessions the local ethernet adapter is inactive and the virtual VPN adapter has to be taken.