I do have a hard time making it work, here's the error log:
Nov 24 16:32:09 AlmondPlus user.info sysinit: Fri Nov 24 16:32:09 2017 OpenVPN 2.3.4 arm-openwrt-linux-gnu [SSL (OpenSSL)] [LZO] [EPOLL] [MH] [IPv6] built on Jul 17 2015
Nov 24 16:32:09 AlmondPlus user.info sysinit: Fri Nov 24 16:32:09 2017 library versions: OpenSSL 1.0.1k 8 Jan 2015, LZO 2.04
Nov 24 16:32:09 AlmondPlus user.info sysinit: Fri Nov 24 16:32:09 2017 WARNING: file '/etc/openvpn/vpn.conf' is group or others accessible
Nov 24 16:32:09 AlmondPlus user.info sysinit: Fri Nov 24 16:32:09 2017 Cannot load inline certificate file: error:0906D06C:lib(9):func(109):reason(108): error:140AD009:lib(20):func(173):reason(9)
Nov 24 16:32:09 AlmondPlus user.info sysinit: Fri Nov 24 16:32:09 2017 Exiting due to fatal error