your wax material doesn't appear to be very dense. it looks like you used a single sided sss instead of a solid becuase the candle itself looks hollow. it needs a higher Coefficient and Asymmetry values...... but the biggest issue is with your exposures not lining up at all between the emission of the single candle flame and the environment it is in. of course, I'm expecting everything I just said to go right over your head, but i hope that assumption is wrong
