If you aren't, it's likely your plugins, which you can fix by gradually removing your plugins one by one until the server gets fixed. Don't worry, plugin files aren't deleted, just the plugin, so you don't have to worry about setting everything back up again. ...
at net.minecraft.class_3324.handler$zii001$minehutplugin$placeNewPlayer(class_3324.java:3508) ~[server-intermediary.jar:?] at net.minecraft.class_3324.method_14570(class_3324.java:289) ~[server-intermediary.jar:?] at net.minecraft.class_3248.method_33800(class_3248.java:151) ~[server-interme...
[12:21:25 ERROR]: org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:615) [12:21:25 ERROR]: net.minecraft.server.players.PlayerList.placeNewPlayer(PlayerList.java:330) [12:21:25 ERROR]: net.minecraft.server.network.ServerLoginPacketListenerImpl.placeNewPlayer(ServerLogin...
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:305) ~[cylonespigot-1.19.2.jar:git-CylonePaper-"3d92c07"] at java.lang.Thread.run(Thread.java:833) ~[?:?] Suppressed: org.spongepowered.configurate.serialize.SerializationException: [fixes, falling-block-height-nerf] o...