When you add your warm water, butter, and milk mixture to the yeast, make sure your temperature is below 130 degrees F. Any more than that and the yeast won't survive (this goes for rapid rise or active dry yeast). Then let it stand for about 5 minutes to activate the yeast before you add your other ingredients and knead the dough. Yeast needs warm water to wake up and start working. This is called u0022proofing.u0022