When in one of the realms for the Blue Skies mod this happens randomly. Is client side i think cause the server doesnt crash.

The game crashed whilst unexpected error
Error: java.lang.NullPointerException: Cannot invoke "net.minecraft.client.resources.sounds.SoundInstance.m_8070_()" because the return value of "net.minecraftforge.client.event.sound.PlaySoundEvent.getSound()" is null
Exit Code: -1

Have you updated to the newest vesion? This looks like an issue we had last week that was fixed.

Have you tried repairing your instance? It seems that your missing a sound somewhere

I had the same issue, which happened with the new update the first time I launched but haven't had the crash happen since, updated the modpack 5 hours ago and launched it 4 times.

Have you tried repairing your instance? It seems that your missing a sound somewhere

It tried a fresh install and still didnt work. I hoping that when i can update the server it will fix it.