The OpenVpn application needs an additional adapter to can work well. The Tap-Win32 virtual ethernet adapter will be installed during the application installation or can be added later. Something went wrong, because I have tried everything, also running as administrator, troubleshooting, enable/disable, reinstall, but always will be going this to a failed status.
But without this adapter the connection will be failed too. What can to do then?
It seems that the problem is solved by downloading the newest standalone Tap driver from OpenVpn repository.