Candida is the most known yeast but there are quite a few culprits there.
So If the question was phrased :
so does this mean the problem is yeast?
Most likely yes! But beware often candida/yeast sufferer do not get to feel better at first when they use fluconazole - they get to have pleny of die-off symptoms - due to yeast dying off fast.
So this is not an absolute "yes"
However sinus and yeast are very much related and getting rid of the yeast is one thing furthermore establishing a healthy flora is quite important and as such is likely to be part of your protocol.