[WARNING] .... [MMOCore] Task #3178 for MMOCore v1.2.3 generated an exception

java.lang.NoClassDefFoundError: net/Indyuce/mmoitems/MMOItems

at net.Indyuce.mmocore.api.player.PlayerData.giveExperience(PlayerData.java:493) ~[?:?]

at net.Indyuce.mmocore.api.experience.source.type.ExperienceSource.giveExperience(ExperienceSource.java:51) ~[?:?]

at net.Indyuce.mmocore.api.experience.source.type.SpecificExperienceSource.giveExperience(SpecificExperienceSource.java:33) ~[?:?]

at net.Indyuce.mmocore.api.experience.source.KillMobExperienceSource$1$1.run(KillMobExperienceSource.java:43) ~[?:?]

at org.bukkit.craftbukkit.v1_15_R1.scheduler.CraftTask.run(CraftTask.java:84) ~[patched_1.15.1.jar:git-Paper-62]

at org.bukkit.craftbukkit.v1_15_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:452) ~[patched_1.15.1.jar:git-Paper-62]

at net.minecraft.server.v1_15_R1.MinecraftServer.b(MinecraftServer.java:1179) ~[patched_1.15.1.jar:git-Paper-62]

at net.minecraft.server.v1_15_R1.DedicatedServer.b(DedicatedServer.java:417) ~[patched_1.15.1.jar:git-Paper-62]

at net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:1106) ~[patched_1.15.1.jar:git-Paper-62]

at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:933) ~[patched_1.15.1.jar:git-Paper-62]

at java.lang.Thread.run(Thread.java:813) [?:1.8.0_212]