Trouble with Net library ('Couldn't write type 6') + Should I be using Net at all?

I can’t figure out what this ‘Couldn’t write type 6’ error means, and the wiki doesn’t mention it either. My setup is actually more complex then this, but here is an breakdown of what my problem is.



local meta = FindMetaTable("Player")
Function meta:UpdateLocalData()
    local data = self.data 

    net.Start("PlayerData")
        net.WriteTable(data)
    net.Send(self)
    
    timer.Simple(1,function() self:UpdateLocalData() end)
end


Clientside:



local Data = {}

function ReceiveData()
	Data = net.ReadTable()
end

net.Receive("PlayerData", ReceiveData)


Now while this does actually work my console gets filled up with '‘Couldn’t write type 6’ errors. This doesn’t seem to happen for the first iteration, but the ones after that (Timer loop) do seem to give an error. I’ve checked and the table is genuinely filled, so it’s not trying to send empty data. I’m at a loss at why it would error then.

On a second thought: I’ve been doubting whether I should use NetworkVars to keep data updated clientside or just continuously send Net messages. I remember reading that NetworkVars shouldn’t be set constantly, and the player data in question does change constantly. Does it make a big difference in the long run?

Your table might have a function in it, you can’t send functions

Thank you! I Accidentally put a class in the data (which contains functions).