Securifi has said that there are problems with their L2TP VPN. Hopefully those will be cleared up quickly. I have had no problem connecting to the OpenVPN on my Raspberry PI, which is behind the Almond+. I just set up port fowarding, I believe it was under Advanced->Forwarding (not Firewall). If your Mac is set up as an L2TP server, then you should make sure L2TP is turned off on the Almond+, and then I think the Forwarding should be all you need.