Unable to cast value to object? I'm not sure what this means, my code looks fine.

Hi, I'm making a system where I want to fire a specific client with the value of Experience which is in an object. I know I have the right path to all the things including my variables, I just don't know what is causing this error. Here is my script for server. My local script works perfectly fine, the error is appearing in the server script.

local rS = game:GetService("ReplicatedStorage")
local remoteEvents = rS.RemoteEvents
local dmgEv = remoteEvents.Damaged

dmgEv.OnServerEvent:Connect(function(plr, block, dmg, waitingTime)
	print(block.Name.." is the block")
	if block.Health.Value >= dmg then
		wait(waitingTime)
		block.Health.Value = block.Health.Value - dmg
		if block.Health.Value == 0 then
			plr.Experience.Value = plr.Experience.Value + block.Experience.Value
			block.Anchored = false
			print(block:WaitForChild("Experience").Value) --//Prints
			remoteEvents:WaitForChild("XpNotify"):FireClient(block:WaitForChild("Experience").Value)
		end
	else
		wait(waitingTime)
		if block.Health.Value ~= 0 then
			plr.Experience.Value = plr.Experience.Value + block.Experience.Value
			block.Health.Value = 0
			block.Anchored = false
			remoteEvents.XpNotify:FireClient(block.Experience.Value)
		else
			remoteEvents.XpNotify:FireClient(block.Experience.Value)
			block.Health.Value = 0
			plr.Experience.Value = plr.Experience.Value + block.Experience.Value
		end
	end
end) 

The error occurs on this line

remoteEvents:WaitForChild("XpNotify"):FireClient(block:WaitForChild("Experience").Value)

22:28:39.785 - Unable to cast value to Object

Thanks for your time. All help is appreciated.