Behind vpn and dns. No connection

[hedztrem]

So if you are outside the home, connected to your VPN, the DDNS address does not work, correct?  Do you have NAT loopback enabled in the router?

Hmm i hear my knowledge isnt enough. How do you mean connected to my vpn when im outside the house. I bought 1 month from ovpn.com. So the only thing i tried is there app for iphone. But that has nothing to do with my home. 
Have i missed something i must set up to get the connection to my computer at home? I thought the dns adress with port forward was enough.

My ddns work from outside home. If I disable openvpn in the router. But that's not what i want. 

NAT loopback seems activeted by default (after a Quick googling)