triggerClientEvent

[Snow-Man]

everytime, when i use triggerClientEvent, it's doesn't work but sometimes do

it's said client event isn't added

here my script 

server : 

function onMarkerBankHit(player, matchingDimension)
	if getElementData(source, "USC.Bank") and not isGuestAccount(hitPlayer)  then
	if (getElementType(player) ~= "player" or not matchingDimension) then return end
	if (isPedInVehicle(player) or not isPedOnGround(player)) then return end
		local account = getAccountName(getPlayerAccount(player))
		triggerClientEvent(player,"USCbank:showBankGUI",player,account)
	end
end
addEventHandler("onMarkerHit", root, onMarkerBankHit)

client :

addEvent("USCbank:showBankGUI", true)	
addEventHandler("USCbank:showBankGUI", root,
function (account)
	guiSetVisible(USC.window[1], true)
	showCursor(true)
	guiSetText(USC.label[1], "Account Name : "..account)
end)