The expanse of featureless sky plus the more exposed foreground serve to mute the impact of the sunset giving the whole image that dullness that Ash refers to. Also the composition itself doesn't make for an interesting perspective.
If you crop out about half the sky you'll see what I mean, the perspective changes and the sunset becomes more dominant. I would also crop just a little from the left to get rid of that partial tree just entering the frame which is a little distracting.
It's nice that you got some foreground interest on the right of the frame but unfortunately the position of the road at bottom left doesn't make for nice composition either. If you had taken the picture with the road entering the shot form the bottom of the frame, it would make a nice diagonal leading the viewer into the image.
Keep it up though, we learn more from our mistakes than our successes.