This works, increases my level by 1
game.ReplicatedStorage.RemoteEvents.lvlUp.OnServerEvent:Connect(function(player, exp)
player.Stats.Lvl.Value = player.Stats.Lvl.Value+1
player.Stats.Exp.Value = exp
end)
However, when I add some things my level goes to 0 on level, why?
game.ReplicatedStorage.RemoteEvents.lvlUp.OnServerEvent:Connect(function(player, exp)
player.Stats.Lvl.Value = player.Stats.Lvl.Value+1
player.Stats.Value = player.Stats.Value + 3
player.Stats.Strength.Value = player.Stats.Strength.Value + 1
player.Stats.Agility.Value = player.Stats.Agility.Value + 1
player.Stats.Intelligence.Value = player.Stats.Intelligence.Value + 1
player.Stats.Defense.Value = player.Stats.Defense.Value + 1
player.Stats.Vitality.Value = player.Stats.Vitality.Value + 1
player.Stats.Dexterity.Value = player.Stats.Dexterity.Value + 1
player.Stats.Exp.Value = exp
end)

3 comments
What is player.Stats.Value = player.Stats.Value + 3? Is there intentionally no specified stat? I'm not sure how you set up the leveling system so I don't have much to work with.
The Stats holds the stat points used to upgrade the strength agi intelligence etc2. the level value is also in stat value
You sould not have a remote event that levels a player up when called anyone can call it if you include no checks.