Player capability vampirism

[User Authenticator #4/INFO] [net.minecraft.network.login.ServerLoginNetHandler/]: UUID of player Tygrako is ca9068aa-0639-4876-b76e-206057ada228
[21Feb2020 22:09:51.062] [Server thread/WARN] [de.teamlapen.vampirism.player.vampire.VampirePlayer/]: Cannot get Vampire player capability. This might break mod functionality.
java.lang.Throwable: null
	at de.teamlapen.vampirism.player.vampire.VampirePlayer.getOpt(VampirePlayer.java:107) [?:1.6.0-alpha+20200218-1132]
	at de.teamlapen.vampirism.player.ModPlayerEventHandler.eyeHeight(ModPlayerEventHandler.java:335) [?:1.6.0-alpha+20200218-1132]
	at net.minecraftforge.eventbus.ASMEventHandler_988_ModPlayerEventHandler_eyeHeight_EyeHeight.invoke(.dynamic) [?:?]
	at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) [eventbus-1.0.0-service.jar:?]
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) [eventbus-1.0.0-service.jar:?]
	at net.minecraft.entity.Entity.getEyeHeightForge(Entity.java:2761) [?:?]
	at net.minecraft.entity.Entity.<init>(Entity.java:220) [?:?]
	at net.minecraft.entity.LivingEntity.<init>(LivingEntity.java:192) [?:?]
	at net.minecraft.entity.player.PlayerEntity.<init>(PlayerEntity.java:162) [?:?]
	at net.minecraft.entity.player.ServerPlayerEntity.<init>(ServerPlayerEntity.java:162) [?:?]
	at net.minecraft.server.management.PlayerList.func_148545_a(PlayerList.java:379) [?:?]
	at net.minecraft.network.login.ServerLoginNetHandler.func_147326_c(ServerLoginNetHandler.java:116) [?:?]
	at net.minecraft.network.login.ServerLoginNetHandler.func_73660_a(ServerLoginNetHandler.java:63) [?:?]
	at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:224) [?:?]
	at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:135) [?:?]
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:846) [?:?]
	at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:324) [?:?]
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:764) [?:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:622) [?:?]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_242]