Minecraft java edition 1.17.1 server acting weird

I have a 1.17.1 paper server for me and my friends to play on but if you die in the game you cannot respawn and the server must be restarted so you can join. I’m not sure if this is because of my firewall but if i join my survival server (the same issue occurs with or without a waterfall proxy) via my local IP it works fine, but if i join with my public IP i have the death and join issues. I really want to have a seamless play session on my server, when i had a 1.12.2 server setup with the same firewall and such it worked fine. Any help is very much appreciated!

System details: ubuntu 20.04, linux kernal 5.11.10, x86_64