Friends can't access Minecraft Server (Ubuntu Server)?

Hi. I have an Ubuntu server. But my friends can't do it. I've already released port and so on (with sudo ufw…) I can use it myself (and other computers in the household too).

UFW status:

I always use the IP that I got with "hostname -i". But recently the IP has changed and with the new IP even I can't figure it out anymore (the new IP is 127.0.1. The old IP (with which I still get it: 192.168.2.115)

Can anyone help me?

I always use the IP that I got with "hostname -i".

It's internal. Nobody outside of your own LAN can do anything with it.

I also made port sharing on the router for a long time

Of course, the external users need the current * external * IP of your router in order to connect.

How do I find out?

Either the router shows you the or, for example

https://www.whatismyip.com/