Port forwarding not working as expected

[richardmountain]

I'm running version: OPNsense 17.7.12-amd64

I have a couple of ports forwarded which are working fine.

Let's say for example I've got the port 12345 forwarded and it's working a treat, I've tried to copy the rule by clicking on the copy icon and just changed the port to 12346.

Now port 12345 is still open without issue but port 12346 isn't open, am I missing something?