changed the title Internal Exception: java.lang.IllegalArgumentException: Registry ResourceKey [minecraft:root / apoli:configured_entity_condition] was missing.

Minecraft Internal Exception errors can be frustrating to get rid of if you do not know what to do.

To fix Internal Exception: java.io.IOException, An existing connection was forcibly closed by the remote host Minecraft error, you need to follow the given solutions.

The Internal Exception Java.IO.IOException error usually occurs when you launch Minecraft, or when the game is underway. This error can be caused by a number of different things.

java.lang.ClassCastException: class net.minecraft.server.network.ServerGamePacketListenerImpl cannot be cast to class net.minecraft.network.protocol.game.ClientGamePacketListener (net.minecraft.server ...