I need help, when a user dies it loses the prefix and in the tag it is bug with the name of some users

This is likely another plugin or the server software itself. Try removing plugins one by one, and see if it affects the nametag on death.

i have 60 plugins....

What version of minecraft? It's probably another plugin that is resetting the player's metadata/scoreboard etc.

1.8

Do you have a plugin that changes the player's scoreboard when they die? Perhaps a KitPVP plugin, mcMMO, factions etc.

no

If you have access to the console. You can type pl and copy and paste a list here.

PlaceholderAPI, Announcer, SpawnJoin, SetLobby, NametagEdit, TopTenHeads, AntiJoinBot, ViaVersion, Tablist, KitsCreator, AntiCrash, WorldEdit, EmptyWorldGenerator, HealthBar, Essentials, VipSlot, ClearLag, BuycraftX, Reputation, ProtocolLib, NoCheatPlus, EssentialsChat, PermissionsEx, Vault, ServerListPlus, MassiveCore, CrashFix, PerWorldInventory, CreativeGates, LWC, KillerMoney, WorldGuard, ChestCommands, EssentialsProtect, EssentialsAntiBuild, ServerSigns, PlayerHeads, ShopGUIPlus, FrameProtect, CommandBlocker, PlotMe, HeadDatabase, 1vs1, Citizens, ChestShop, PlotMe-DefaultGenerator, Multiverse-Core, MineResetLite, SkyWarsReloaded, AuthMe, Jail, HolographicDisplays, SkinsRestorer, IslandWorld, Multiverse-NetherPortals, MultiWorldMoney, CombatLog

How is this closed??