I have been getting this issue on my server with a few players. They attempt to login and then it immediately disconnects them. I am running the latest Forge, SpongeForge, and Pixelmon Reforged mods along with others Sponge mods. I’m pretty sure it is something happening on the user’s end rather than the server’s but I just want to get clarification. Thanks!
The information you’re getting in the console is normal. It just means someone left the server and Minecraft didn’t tell the server before it disconnected. However, being disconnected when logging in is unexpected. I believe the players should see a message on their screen when they get kicked. Could you post that message here?