Tying a knot successfully in a dream means that you're holding a particularly difficult situation together.
Perhaps this is personal; your friend or family member is going through a difficult time and you have been their main support. Whatever the predicament, you have been the glue holding everything together or have found you are stronger than you might have once thought.
A knot that is easily loosened means that you are also able to escape any commitment that prevents your progress or holds you back. This may have been part of the process keeping things on an even keel- you might have let go of something or someone else in order to make this period flow more smoothly for everyone involved.
Another thought is that it symbolises your connections with those around you- be it a partner, family, friends or work colleagues. If all if your relationships are going well lately- this might be why you dreamt about a knot. With that said, if the knot was too tight- your relationships might be stifling you at present. Do you need to tell those involved that you require some space?
You may like life to be uncomplicated; a knot can mean that you are tangled up in something that you don't wish to be- but given your history- you will probably find a way out it just may not be clear right now.
More specifically, putting a knot together can also be interpreted as you having some confusion in your life right now.
Source: The Complete A-Z Dictionary of Dreams by Ian Wallace
Tagged in Dream Interpretation