Bug Report

Type /ver NametagEdit and post the output.
4.4.10

What version of Bukkit/Spigot/PaperSpigot are you using? Type /ver
git-Spigot-0509002-6b95d59 (MC:1.16.1) API: version 1.16.1-R0.1-SNAPSHOT

What plugins are you using? Type /plugins
LuckPerms, WorldEdit, ClearChat, PlaceholderAPI, ClearLag, PlugMan, PlayTime, NametagEdit, HolographicDisplays, EndlessEnchant, WorldGuard, AdvancedPortals, DeluxeTags, VoidGenerator, VoxelSniper, PlaceItemsOnGroundRebuilt, MOTD, Vault, Lores, CratesPlus, CoreProtect, ShopGUIPlus, ChatColor2, Scoreboard-revision, Essentials, BlockRegen, ActionHealth, Multiverse-Core, Citizens, EssentialsXMPP, CustomEnchants, LockettePro, CustomHeads, JetsMinions, Quests, EssentialsGeoIP, EssentialsChat, Duels, EpicCraftingsPlus, PlayerVaults, EssentialsSpawn, WorldGuardExtraFlags, BlockParticles, IridiumSkyblock, dtlTraders.

Please explain your issue. How do you trigger it?
Modifying the prefix from the API 'NametagEdit.getApi().setPrefix(player, Prefix);'
I myself was unable to recreate this but another person was I've added some checks and it seems like the faketeam doesn't even exist for the player?
I even added a check to prevent it from modifying the prefix if the team is null but that causes my plugin not to work properly as it isn't able to update the prefix.

It's not an issue that happens to all users just a few so has to have a cause...
This error is so bad it even causes servers to crash/reboot...

Are there any errors in the console? Please use: https://pastebin.com
https://pastebin.com/paGtt3A8