NullPointerException on DynMap

[SpraxDev]

org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.PlayerList.onPlayerJoin(PlayerList.java:327) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.PlayerList.a(PlayerList.java:160) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.LoginListener.b(LoginListener.java:147) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.LoginListener.F_(LoginListener.java:57) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.NetworkManager.a(NetworkManager.java:233) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.ServerConnection.c(ServerConnection.java:140) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.MinecraftServer.D(MinecraftServer.java:842) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.DedicatedServer.D(DedicatedServer.java:399) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.MinecraftServer.C(MinecraftServer.java:678) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:576) [spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at java.lang.Thread.run(Thread.java:748) [?:1.8.0_144]
Caused by: java.lang.NullPointerException
        at org.dynmap.bukkit.DynmapPlugin.assertPlayerInvisibility(DynmapPlugin.java:1511) ~[?:?]
        at bammerbom.ultimatecore.bukkit.listeners.DynmapListener.onJoin(DynmapListener.java:149) ~[?:?]
        at sun.reflect.GeneratedMethodAccessor370.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_144]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_144]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigot.jar:git-Spigot-3fb9445-6e3cec8]
        ... 14 more

Didn't do anything. Just printed out in Console. A player on the Server was/is invisible/vanish - Maybe that's the reason.