Unsure of why I have an error with an embedded if statement using 'else'?

Within my code I have an embedded if statement which uses the else, however on the first if statement whenever I use else again for the highest if statement it just causes an error and I'm not sure why. Here is my code:

if challengeLength > enteredLength then
	if challengeString == enteredText then
		print("CORRECT")
	else
		enteredLength = enteredLength - 1
		print("Incorrect")	
else -- This is the else that it causes an error on
	print("Done")
	end	
end