Problème connexion serveur minecraft

[Starx_]

bonjour, je n'arrive pas à me connecter à un serveur moddé, je stagne en "logging in" et voici l'erreur LOG :

21:54:39] [Client thread/FATAL] [net.minecraft.client.Minecraft]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
    at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_74]
    at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_74]
    at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?]
    at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1088) [bib.class:?]
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:398) [bib.class:?]
    at net.minecraft.client.main.Main.main(SourceFile:123) [Main.class:?]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_74]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_74]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_74]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_74]
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
Caused by: java.lang.NullPointerException

si quelqu'un pourrait m'aider à trouver une solution, merci beaucoup !