A couple of words of clarification: first, Pro Mix HP is just peat and perlite, there is nothing inherently antifungal about it. That does not mean it is no good, in fact it is an ideal medium, I just prefer a higher ratio of perlite in my rooting mix. I soak my cuttings in Chinosol antifungal before rooting. Expensive, but it works. Second, there is no consideration mentioned here as to rooting temperature. If you are not in the sweet spot, 78-80 degrees F, you may have a problem. Ideal temps and humidity are more important than the medium. And don't overwater. Finally, there is the question of rooting hormone, which is optional.