Server Issues for 1.16 server, but not 1.12

[LongTimeGamer]

Hello! So for some reason, I'm not able to get my Direwolf20 1.16 server to allow my friends to join. They start loading in, sometimes they get in for a few seconds, then they are kicked with the "Internal Exception: java.io.IOException: An existing connection was forcibly closed by the remote host" error. I'm currently on Windows 10, I am trying to create my own server, and I'm allocating 6-7GB of ram to said server. I don't understand why this is happening, as I have a 1.12 server that works just fine. If you need any other documents, please let me know.

 

[LongTimeGamer]

I tried creating a server on the 1.16 Unstable modpack, and it does the same exact thing. Gets to the could not serialize line, then the player joining is kicked. As mentioned before, I am currently able to host a 1.12 Minecraft server just fine with my friends joining me. It must just have to do with the way 1.16 handles servers or possibly new settings they added to the properties.