When I use a fireball this error comes up in console:

Could not pass event EntityDamageByEntityEvent to Parties v3.2.13
org.bukkit.event.EventException: null
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[patched_1.8.8.jar:git-PaperSpigot-445]
at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:78) ~[patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:517) [patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:502) [patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.craftbukkit.v1_8_R3.event.CraftEventFactory.callEvent(CraftEventFactory.java:87) [patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.craftbukkit.v1_8_R3.event.CraftEventFactory.handleEntityDamageEvent(CraftEventFactory.java:445) [patched_1.8.8.jar:git-PaperSpigot-445]
at org.bukkit.craftbukkit.v1_8_R3.event.CraftEventFactory.handleLivingEntityDamageEvent(CraftEventFactory.java:585) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.EntityLiving.d(EntityLiving.java:1112) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.EntityHuman.d(EntityHuman.java:860) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.EntityLiving.damageEntity(EntityLiving.java:748) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.EntityHuman.damageEntity(EntityHuman.java:801) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.EntityPlayer.damageEntity(EntityPlayer.java:504) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.Explosion.a(Explosion.java:138) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.World.createExplosion(World.java:1916) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.WorldServer.createExplosion(WorldServer.java:1053) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.EntityLargeFireball.a(EntityLargeFireball.java:32) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.EntityFireball.t_(EntityFireball.java:130) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.World.entityJoinedWorld(World.java:1650) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.World.g(World.java:1617) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.World.tickEntities(World.java:1450) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.WorldServer.tickEntities(WorldServer.java:600) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:846) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:378) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:713) [patched_1.8.8.jar:git-PaperSpigot-445]
at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:616) [patched_1.8.8.jar:git-PaperSpigot-445]
at java.lang.Thread.run(Thread.java:834) [?:?]
Caused by: java.lang.NoClassDefFoundError: org/bukkit/entity/SpectralArrow
at com.alessiodp.parties.bukkit.listeners.BukkitFightListener.onPlayerHit(BukkitFightListener.java:54) ~[?:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
at java.lang.reflect.Method.invoke(Method.java:566) ~[?:?]
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:300) ~[patched_1.8.8.jar:git-PaperSpigot-445]
... 26 more

Its a known issue, I will release a fix for it. You can use 3.2.12 until a fix is released.

Its a known issue, I will release a fix for it. You can use 3.2.12 until a fix is released.

Ok no problem, thank you for your reply

Fixed with 3.2.14