Hello, When I launch my server, I have this error: [18:26:09 ERROR]: Could not load 'plugins/Vault.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.IllegalArgumentException: Plugin already initialized!
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:133) ~[patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:331) ~[patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:254) [patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugins(CraftServer.java:293) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.DedicatedServer.init(DedicatedServer.java:202) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:563) [patched_1.8.8.jar:git-PaperSpigot-445]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_312]
Caused by: java.lang.IllegalArgumentException: Plugin already initialized!
at org.bukkit.plugin.java.PluginClassLoader.initialize(PluginClassLoader.java:123) ~[patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.plugin.java.JavaPlugin.(JavaPlugin.java:66) ~[patched_1.8.8.jar:git-PaperSpigot-445]
at net.milkbowl.vault.Vault.(Vault.java:106) ~[?:?]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_312]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:1.8.0_312]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:1.8.0_312]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[?:1.8.0_312]
at java.lang.Class.newInstance(Class.java:442) ~[?:1.8.0_312]
at org.bukkit.plugin.java.PluginClassLoader.(PluginClassLoader.java:77) ~[patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:129) ~[patched_1.8.8.jar:git-PaperSpigot-445]
... 6 more

    Can you help me please ? Thank you in advance

Oh ok. I will see

It's working. Thank you so much

Did you do new Vault() anywhere? regardless this should not be a problem that is caused if it isn't for the presence of fault 3rd party plugins