error

[20:05:29] [Server thread/INFO] [sx.blah.discord.Discord4J]: Discord4J v2.10.1 9b1c81a (https://github.com/austinv11/Discord4J)
[20:05:29] [Server thread/INFO] [sx.blah.discord.Discord4J]: A Java binding for the official Discord API, forked from the inactive https://github.com/nerd/Discord4J. Copyright (c) 2017, Licensed under GNU LGPLv3
[20:05:30] [Server thread/ERROR] [Sponge]: Could not pass GamePreInitializationEvent$Impl to Plugin{id=theforgecore, name=TheForge Core, version=0.1.0, description=The core aspects of TheForge server, url=https://gitlab.com/theforgemc/theforge-core, authors=[NeusFear], source=mods\theforge-core-0.1.0.jar}
java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ObjectMapper
	at sx.blah.discord.api.internal.DiscordUtils.<clinit>(DiscordUtils.java:80) ~[DiscordUtils.class:?]
	at sx.blah.discord.api.events.EventDispatcher.<init>(EventDispatcher.java:78) ~[EventDispatcher.class:?]
	at sx.blah.discord.api.internal.DiscordClientImpl.<init>(DiscordClientImpl.java:158) ~[DiscordClientImpl.class:?]
	at sx.blah.discord.api.ClientBuilder.build(ClientBuilder.java:416) ~[ClientBuilder.class:?]
	at neusfear.theforgecore.TheForgeCore.onPreInitialization(TheForgeCore.java:81) ~[TheForgeCore.class:?]
	at org.spongepowered.common.event.listener.GamePreInitializationEventListener_TheForgeCore_onPreInitialization10.handle(Unknown Source) ~[?:?]
	at org.spongepowered.common.event.RegisteredListener.handle(RegisteredListener.java:95) ~[RegisteredListener.class:1.12.2-7.1.0-BETA-59]
	at org.spongepowered.common.event.SpongeEventManager.post(SpongeEventManager.java:423) [SpongeEventManager.class:1.12.2-7.1.0-BETA-59]
	at org.spongepowered.common.event.SpongeEventManager.post(SpongeEventManager.java:459) [SpongeEventManager.class:1.12.2-7.1.0-BETA-59]
	at org.spongepowered.common.SpongeImpl.postEvent(SpongeImpl.java:223) [SpongeImpl.class:1.12.2-7.1.0-BETA-59]
	at org.spongepowered.common.SpongeImpl.postState(SpongeImpl.java:231) [SpongeImpl.class:1.12.2-7.1.0-BETA-59]
	at org.spongepowered.server.SpongeVanilla.preInitialize(SpongeVanilla.java:121) [SpongeVanilla.class:1.12.2-7.1.0-BETA-59]
	at net.minecraft.server.dedicated.DedicatedServer.handler$onServerLoad$zpo000(SourceFile:1234) [nz.class:?]
	at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(SourceFile:117) [nz.class:?]
	at net.minecraft.server.MinecraftServer.run(SourceFile:434) [MinecraftServer.class:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_191]
Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.databind.ObjectMapper
	at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:101) ~[launchwrapper-1.12.jar:?]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_191]
	at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_191]
	... 16 more