Cannot invoke "java.util.Map.put(Object, Object)" because the return value of "java.util.Map.get(Object)" is null

[heytek]

java.lang.NullPointerException: Cannot invoke "java.util.Map.put(Object, Object)" because the return value of "java.util.Map.get(Object)" is null
at fr.minuskube.netherboard.bukkit.BPlayerBoard.sendScore(BPlayerBoard.java:212) ~[?:?]
at fr.minuskube.netherboard.bukkit.BPlayerBoard.set(BPlayerBoard.java:104) ~[?:?]
at fr.minuskube.netherboard.bukkit.BPlayerBoard.setAll(BPlayerBoard.java:128) ~[?:?]
at me.heytek.utils.ScoreboardUtil.updateStats(ScoreboardUtil.java:98) ~[?:?]
at me.heytek.listeners.DeathListener$1.run(DeathListener.java:42) ~[?:?]
at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:100) ~[patched_1.16.5.jar:git-Patina-ver/1.16.5-"667fb1b"]
at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:58) ~[patched_1.16.5.jar:git-Patina-ver/1.16.5-"667fb1b"]
at com.destroystokyo.paper.ServerSchedulerReportingWrapper.run(ServerSchedulerReportingWrapper.java:22) ~[patched_1.16.5.jar:git-Patina-ver/1.16.5-"667fb1b"]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) [?:?]
at java.lang.Thread.run(Thread.java:831) [?:?]

[MinusKube]

(Sorry for the late answer)

It seems like you're updating the scoreboard within an async task, Netherboard is not thread-safe, so you'll have to update the scoreboard within the main thread.