There is a bug with the eco plugin starting with 6.53.1 version of the plugin.
[16:36:49] [Server thread/ERROR]: Could not pass event PlayerQuitEvent to eco v6.53.1 org.bukkit.event.EventException: null at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:589) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:576) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] at net.minecraft.server.players.PlayerList.remove(PlayerList.java:520) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.network.PlayerConnection.a(PlayerConnection.java:1788) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.network.NetworkManager.m(NetworkManager.java:444) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.network.ServerConnection.c(ServerConnection.java:195) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.MinecraftServer.b(MinecraftServer.java:1326) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.dedicated.DedicatedServer.b(DedicatedServer.java:388) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:1200) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:1017) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.MinecraftServer.lambda$0(MinecraftServer.java:304) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at java.lang.Thread.run(Thread.java:833) ~[?:?] Caused by: java.lang.IllegalAccessError: class com.willfp.eco.internal.spigot.proxy.v1_19_R3.common.packet.PacketInjectorListener tried to access private field net.minecraft.server.network.PlayerConnection.h (com.willfp.eco.internal.spigot.proxy.v1_19_R3.common.packet.PacketInjectorListener is in unnamed module of loader org.bukkit.plugin.java.PluginClassLoader @3a0e96cb; net.minecraft.server.network.PlayerConnection is in unnamed module of loader java.net.URLClassLoader @7daf6ecc) at com.willfp.eco.internal.spigot.proxy.v1_19_R3.common.packet.PacketInjectorListener.onLeave(PacketInjectorListener.kt:34) ~[?:?] at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?] at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?] at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?] at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?] at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] ... 13 more
There is a bug with the eco plugin starting with 6.53.1 version of the plugin.
[16:36:49] [Server thread/ERROR]: Could not pass event PlayerQuitEvent to eco v6.53.1 org.bukkit.event.EventException: null at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:589) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:576) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] at net.minecraft.server.players.PlayerList.remove(PlayerList.java:520) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.network.PlayerConnection.a(PlayerConnection.java:1788) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.network.NetworkManager.m(NetworkManager.java:444) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.network.ServerConnection.c(ServerConnection.java:195) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.MinecraftServer.b(MinecraftServer.java:1326) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.dedicated.DedicatedServer.b(DedicatedServer.java:388) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:1200) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:1017) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at net.minecraft.server.MinecraftServer.lambda$0(MinecraftServer.java:304) ~[spigot-1.19.4-R0.1-SNAPSHOT.jar:3703-Spigot-6ad4b93-e142fb9] at java.lang.Thread.run(Thread.java:833) ~[?:?] Caused by: java.lang.IllegalAccessError: class com.willfp.eco.internal.spigot.proxy.v1_19_R3.common.packet.PacketInjectorListener tried to access private field net.minecraft.server.network.PlayerConnection.h (com.willfp.eco.internal.spigot.proxy.v1_19_R3.common.packet.PacketInjectorListener is in unnamed module of loader org.bukkit.plugin.java.PluginClassLoader @3a0e96cb; net.minecraft.server.network.PlayerConnection is in unnamed module of loader java.net.URLClassLoader @7daf6ecc) at com.willfp.eco.internal.spigot.proxy.v1_19_R3.common.packet.PacketInjectorListener.onLeave(PacketInjectorListener.kt:34) ~[?:?] at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?] at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?] at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?] at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?] at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot-api-1.19.4-R0.1-SNAPSHOT.jar:?] ... 13 more