If you are turning the knob, it shows how you are dealing with the issues in your waking life. If it works smoothly, you are going great. The knob also represents you confidence and self-trust while entering the new phases of your life. The knob may symbolize your desire for better knowledge, you tend to like learning new things and creating new stuff. If you dream that the door knob doesnt work and you are unable to open the door with it, it means that you feel helpless in some situation, because the circumstances are not favorable to you.
Read more about dreaming of Knob in other dream meanings interpretations.