---- Minecraft Crash Report ----

WARNING: coremods are present:
Contact their authors BEFORE contacting forge

// Why did you do that?

Time: 3/9/21 11:33 PM
Description: There was a severe problem during mod loading that has caused the game to fail

net.minecraftforge.fml.common.LoaderException: java.lang.NoClassDefFoundError: net/minecraftforge/client/event/GuiScreenEvent$BackgroundDrawnEvent
    at net.minecraftforge.fml.common.LoadController.transition(LoadController.java:163)
    at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:733)
    at net.minecraftforge.fml.client.FMLClientHandler.finishMinecraftLoading(FMLClientHandler.java:316)
    at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:491)
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:325)
    at net.minecraft.client.main.Main.main(SourceFile:120)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Caused by: java.lang.NoClassDefFoundError: net/minecraftforge/client/event/GuiScreenEvent$BackgroundDrawnEvent
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
    at java.lang.Class.privateGetPublicMethods(Class.java:2902)
    at java.lang.Class.getMethods(Class.java:1615)
    at net.minecraftforge.fml.common.eventhandler.EventBus.register(EventBus.java:60)
    at dev.meyi.bn.BazaarNotifier.init(BazaarNotifier.java:87)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:553)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
    at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
    at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
    at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
    at com.google.common.eventbus.EventBus.post(EventBus.java:275)
    at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:212)
    at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:190)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
    at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
    at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
    at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
    at com.google.common.eventbus.EventBus.post(EventBus.java:275)
    at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:119)
    at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:731)
    ... 10 more
Caused by: java.lang.ClassNotFoundException: net.minecraftforge.client.event.GuiScreenEvent$BackgroundDrawnEvent
    at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 43 more
Caused by: java.lang.NullPointerException
    at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
    ... 45 more



HELP PLZ 

Quote

WARNING: coremods are present:
Contact their authors BEFORE contacting forge

Just sayin...maybe take a look at your coremods first and check with their developers