LR8 kit Lorawan and Datacake connection-packet forwarding

Hi, I am trying to connect my LR8 device to Datacake server eu1.datacake-lns.com in order to see data readings from my heat meter which is equipped with the correct Lora module

I have entered the correct information in my Datacake account and on the Lora section of the LR8 GUI

The LR8 is connected to the internet behind a Draytek 2926 router. Both have the most recent firmware.

However there is no connection showing on the Datacake site. datacake.co

I suspect that I have a firewall issue with packet forwarding and whilst I have tried various NAT settings I am clearly out of my depth.

i have gone to the IP section on the GUI and then NAT but there are many fields and whilst i have tried various things I get various pop up messages saying the configurations are not accepted

Specifically I have changed
CHAIN to dstnat
Src address to the LAN address of the LR8
DST address ???WHAT should go here? it seems to want the public ip of Datacake’s server whereas I have eu1.datacake-lns.com.
Protocol to UDP
Action to dst-nat

Also, am not clear what rule if any I need to set up on the Draytek router

Any advice very gratefully received.

Thank you