I have been able to do this MANY times on other routers but can't seem to figure this MikroTik setup out. I first enabled UPnP
Enabled - check
Allow to Disable Extneral Interface - check (tried both ways)
Show Dummy Rule - check
None of this seemed to work. In Plex, I get the message that says we were unable to reach it fro outside your network. Then I tried port forwarding. Normally, it is as simple as saying any incoming traffic on port 32400 goes to a specific IP address. Here, there are 30 fields to fill in so it is over my head...
Then, I tried IP ->Firewall->Nat.
src address - blank
dst address - blank (tried a few different things on these)
src port 32400
dst port 32400
in interface - bridge 1 (tried them all)
to address 192.168.2.114 (my plex server)
to ports 32400