Resolved with some manual editing of client file (common problem from internet search) which worked until the next version update of Tunnelblick. Now get an error message in Tunnelblick of obsolete protocol language which caused me to check for firmware update but that didn't resolve either. Worked fine initially, but after OS updates, Tunnelblick version updates, and Asus firmware updates has become a hit or miss. Simple setup, simply load the client file created by the router into Tunnelblick.done. My home computer is the server with the Asus router creating the OpenVPN and client protocol file.

Loved it from overseas where thought I was in States and foreign blocks on programing suddenly wasn't as thought I was back in the States. Primarily set up for remote viewing of security cameras as log into my home network, but VPN capabilities expand far beyond that. I use OpenVPN from private server like you describe and so quirky, hit or miss, almost wonder if should subscribe to a commercial VPN.

Openvpn mac client