Forward specific domains to server

[Groyk]

Hi experts

I am new to Opnsense and I have big trouble forwarding trafic for a specific domain. I have setup ubounddns and everything works in my local network. But if i address the domain from the wan side nothing is happening.

I don't know it i need to create NAT forwarding, or what to do. At the moment both Web and mailserver is the same internal ip.