Port forwarding is always more reliable than UPnP mode. But make sure you set up the static ip address first before doing the port forwarding. With the port forwarding, enable it for both TCP & UDP (actually better to do a separate port forward for each but not necessary.) Also, with the DI-Links, you usually need to both save settings & then reboot the router to get the changes fully operational.

Likewise with Birdy, I'd suggest you choose a high port number to connect to which also includes using that same port number to port forward. As she suggested, a port number between 49152 - 65535.

In your LW settings, change from UPnP to Port Forward & put in the number you port forwarded for each of the connection & listening port areas.