External users can’t connect

I’ve made a mineos server on my trueNAS(aka freeNAS). It works perfectly fine for local users but external users can’t connect.
I’ve configured everything correctly so that’s why I don’t know what else to do and came here for help.

What I’ve done:
Created the server and tested it for local users.
Assigned an IP-adress to the MC server and checked if it used the right port 25565.
Port forwarded that IP using that port and did it for both protocols.

How are the clients connecting in game?

The IP adress they use to connect is the same one I use, “Ip-of-the-server:25565”.

For external user you need to use the external IP-address of your network.

From the client you play minercraft on locally use a service like https://www.whatismyip.com/

Remember that port forwarding forwards the port someone connects to to an internal address from an external:

[internet adress]:portnumber -> portforwarding -> [LAN address]:portnumber

This means you can actually listen to one adress, and forward it to another port internally…