Whenever I go to the server and another player comes the server crashes and that comes with the crash reports:
Time: 25.03.21 10:44
Description: Exception in server tick loop
java.lang.NullPointerException: Exception in server tick loop
at net.minecraft.server.v1_8_R3.LoginListener.d (LoginListener.java:155)
at net.minecraft.server.v1_8_R3.LoginListener.a (LoginListener.java:151)
at net.minecraft.server.v1_8_R3.NetworkManager.l (NetworkManager.java:312)
at net.minecraft.server.v1_8_R3.ServerConnection.c (ServerConnection.java:145)
at net.minecraft.server.v1_8_R3.MinecraftServer.B (MinecraftServer.java:814)
at net.minecraft.server.v1_8_R3.DedicatedServer.B (DedicatedServer.java:374)
at net.minecraft.server.v1_8_R3.MinecraftServer.A (MinecraftServer.java:654)
at net.minecraft.server.v1_8_R3.MinecraftServer.run (MinecraftServer.java:557)
at java.lang.Thread.run (Thread.java:748)
This problem usually occurs when someone is jointing with a hacking client on a server or has active hacks that cause the server to crash.
Which server version are you using? Bukkit, Spigot, Paper, Vanilla? And which Minecraft version?
Spigot 1.8.8 thank you for your answer
Spigot 1.8.8 thank you for your answer