mcmmopartyadminerror

[Async Chat Thread - #81/ERROR]: Could not pass event McMMOPartyChatEvent to mcMMO_Party_Admin v0.6b1
java.lang.NoSuchMethodError: org.bukkit.Server.getOnlinePlayers()[Lorg/bukkit/entity/Player;
	at uk.co.drnaylor.mcmmopartyadmin.listeners.PartyChatListener.PartyChat(PartyChatListener.java:35) ~[?:?]
	at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor376.execute(Unknown Source) ~[?:?]
	at org.bukkit.plugin.EventExecutor$1.execute(EventExecutor.java:44) ~[patched_1.9.jar:git-Paper-511]
	at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:74) ~[patched_1.9.jar:git-Paper-511]
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[patched_1.9.jar:git-Paper-511]
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:517) [patched_1.9.jar:git-Paper-511]
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:499) [patched_1.9.jar:git-Paper-511]
	at com.gmail.nossr50.chat.ChatManager.handleChat(ChatManager.java:25) [mcMMO.jar:?]
	at com.gmail.nossr50.chat.PartyChatManager.handleChat(PartyChatManager.java:23) [mcMMO.jar:?]
	at com.gmail.nossr50.chat.ChatManager.handleChat(ChatManager.java:43) [mcMMO.jar:?]
	at com.gmail.nossr50.listeners.PlayerListener.onPlayerChat(PlayerListener.java:663) [mcMMO.jar:?]
	at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor39.execute(Unknown Source) [?:?]
	at org.bukkit.plugin.EventExecutor$1.execute(EventExecutor.java:44) [patched_1.9.jar:git-Paper-511]
	at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:74) [patched_1.9.jar:git-Paper-511]
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) [patched_1.9.jar:git-Paper-511]
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:517) [patched_1.9.jar:git-Paper-511]
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:499) [patched_1.9.jar:git-Paper-511]
	at net.minecraft.server.v1_9_R1.PlayerConnection.chat(PlayerConnection.java:1303) [patched_1.9.jar:git-Paper-511]
	at net.minecraft.server.v1_9_R1.PlayerConnection.a(PlayerConnection.java:1218) [patched_1.9.jar:git-Paper-511]
	at net.minecraft.server.v1_9_R1.PacketPlayInChat$1.run(PacketPlayInChat.java:39) [patched_1.9.jar:git-Paper-511]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_31]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_31]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_31]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_31]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_31]