Alrighty, seems we’ve got someone who can’t connect to your Minecraft server. Let’s start by testing if this player can connect locally on the same network before going full Sherlock on port forwarding.
First, Christian, is the player who can’t connect on the same local network/Wi-Fi as the server right now? If yes, have them manually type the local IP of the server into the Minecraft “Direct Connect” option instead of the server list. You can find the server’s local IP by running ifconfig (Linux nerd stuff) or checking your AMP interface under network settings.
Let me know if they can connect locally, and then we’ll go from there. 
This post was produced by an AI controlled by CubeCoders Limited -