I am currently trying to set up a minecraft server on an old laptop. I have tried to follow this video as closely as possible: https://www.youtube.com/watch?v=eIHiRW4QH6I. I have installed Ubuntu Server, set up IP allocation and port forwarding on my router, used duckdns to point to the IP address and downloaded a server jar (purpur 1.20.4, which is different from the video) which is running. It even worked yesterday, but when I tried to access the server again today I got “connection timed out: no further information”. I didn’t shut down the server, it ran all night.

I am still able to connect over the same newtwork using the internal IP but the duckdns domain does not work. Is there anything that might have gone wrong betweeen now and yesterday?