NegativeUser

Hi, I'm making my minecraft forge server on version 1.17.1. Whenever I run the server I get this error, I have tried many ways and could not find the solution. Description: Exception in server tick loop java.lang.NullPointerException: Cannot invoke "com.google.gson.JsonArray.iterator()" because "☃" is null at net.minecraft.server.players.StoredUserList.m_11399_(SourceFile:121) ~[server-1.17.1-20210706.113038-srg.jar%2325!:?] {re:classloading} at net.minecraft.server.dedicated.DedicatedPlayerList.m_139596_(SourceFile:83) ~[server-1.17.1-20210706.113038-srg.jar%2325!:?] {re:classloading} at net.minecraft.server.dedicated.DedicatedPlayerList.<init>(SourceFile:22) ~[server-1.17.1-20210706.113038-srg.jar%2325!:?] {re:classloading} at net.minecraft.server.dedicated.DedicatedServer.m_7038_(DedicatedServer.java:169) ~[server-1.17.1-20210706.113038-srg.jar%2325!:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.m_130011_(MinecraftServer.java:659) ~[server-1.17.1-20210706.113038-srg.jar%2325!:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.m_177918_(MinecraftServer.java:258) ~[server-1.17.1-20210706.113038-srg.jar%2325!:?] {re:classloading,pl:accesstransformer:B} at java.lang.Thread.run(Thread.java:831) [?:?] {} crash-report ty