In a traditional soufflé that’s baked, sometimes the soufflé doesn’t rise. The problems arise with the eggs whites. First, you need to completely separate the egg whites from the yolks, with none of the yolk in the whites. Sometimes, a bit of the yolk can sneak into the whites; this needs to be removed. Otherwise, the whites won’t whip up properly. Second, make sure you don’t over whip the whites. Over-whipped whites will keep the soufflé from rising.