For two weeks, my launcher crash (1 time out of 2) when I'm in the multiplayer tab. I think this is a ping problem (finding with logs).

Game crash: http://prntscr.com/ey9o9f

Log Output:

[14:45:33] [Client thread/INFO]: Setting user: ButtOnKil
[14:45:34] [Client thread/INFO]: LWJGL Version: 2.9.4
[14:45:35] [Client thread/INFO]: Reloading ResourceManager: Default, Faithful 1.12-pre8.zip, CrazyLandPack-v1.5.7.zip
[14:45:35] [Sound Library Loader/INFO]: Starting up SoundSystem...
[14:45:35] [Thread-3/INFO]: Initializing LWJGL OpenAL
[14:45:35] [Thread-3/INFO]: (The LWJGL binding of OpenAL. For more information, see http://www.lwjgl.org)
[14:45:35] [Thread-3/INFO]: OpenAL initialized.
[14:45:36] [Sound Library Loader/INFO]: Sound engine started
[14:45:37] [Client thread/INFO]: Created: 2048x1024 textures-atlas
[14:45:59] [Client thread/ERROR]: Can't ping eu.mineplex.com: Internal Exception: java.io.IOException: Une connexion existante a dû être fermée par l’hôte distant
[14:46:00] [Client thread/FATAL]: Reported exception thrown!
f: Ticking screen
at bgu.t(SourceFile:1601) ~[17w15a.jar:?]
at bgu.aw(SourceFile:959) ~[17w15a.jar:?]
at bgu.a(SourceFile:399) [17w15a.jar:?]
at net.minecraft.client.main.Main.main(SourceFile:123) [17w15a.jar:?]
Caused by: java.lang.NullPointerException
at io.netty.bootstrap.Bootstrap.checkAddress(Bootstrap.java:358) ~[patchy-1.0.jar:?]
at io.netty.bootstrap.Bootstrap.doResolveAndConnect(Bootstrap.java:180) ~[patchy-1.0.jar:?]
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:162) ~[patchy-1.0.jar:?]
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:143) ~[patchy-1.0.jar:?]
at bqz.b(SourceFile:241) ~[17w15a.jar:?]
at bqz.a(SourceFile:45) ~[17w15a.jar:?]
at bqz$1.a(SourceFile:144) ~[17w15a.jar:?]
at gd.l(SourceFile:379) ~[17w15a.jar:?]
at bqz.a(SourceFile:254) ~[17w15a.jar:?]
at bls.e(SourceFile:115) ~[17w15a.jar:?]
at bgu.t(SourceFile:1591) ~[17w15a.jar:?]
... 3 more