rare webhook error

[LittleBigBug]

Rarely on server stop this error pops up

[14:38:54 ERROR]: Couldn't pass ProxyShutdownEvent to discordnotify
java.lang.NoClassDefFoundError: club/minnced/discord/webhook/WebhookClient
        at club.minnced.discord.webhook.WebhookCluster.close(WebhookCluster.java:590) ~[?:?]
        at me.truemb.discordnotify.utils.DiscordManager.disconnectDiscordBot(DiscordManager.java:120) ~[?:?]
        at me.truemb.discordnotify.main.DiscordNotifyMain.onDisable(DiscordNotifyMain.java:181) ~[?:?]
        at me.truemb.universal.minecraft.main.VelocityMain.onDisable(VelocityMain.java:73) ~[?:?]
        at me.truemb.universal.minecraft.main.Lmbda$10.execute(Unknown Source) ~[?:?]
        at com.velocitypowered.proxy.event.UntargetedEventHandler$VoidHandler.lambda$buildHandler$0(UntargetedEventHandler.java:56) ~[velocity.jar:3.3.0-SNAPSHOT (git-00ef92bc-b312)]
        at com.velocitypowered.proxy.event.VelocityEventManager.fire(VelocityEventManager.java:597) ~[velocity.jar:3.3.0-SNAPSHOT (git-00ef92bc-b312)]
        at com.velocitypowered.proxy.event.VelocityEventManager.lambda$fire$5(VelocityEventManager.java:478) ~[velocity.jar:3.3.0-SNAPSHOT (git-00ef92bc-b312)]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
        at java.lang.Thread.run(Thread.java:840) [?:?]
Caused by: java.lang.ClassNotFoundException: club.minnced.discord.webhook.WebhookClient
        at com.velocitypowered.proxy.plugin.PluginClassLoader.loadClass0(PluginClassLoader.java:87) ~[velocity.jar:3.3.0-SNAPSHOT (git-00ef92bc-b312)]
        at com.velocitypowered.proxy.plugin.PluginClassLoader.loadClass(PluginClassLoader.java:64) ~[velocity.jar:3.3.0-SNAPSHOT (git-00ef92bc-b312)]
        at java.lang.ClassLoader.loadClass(ClassLoader.java:525) ~[?:?]
        ... 11 more