You need perfectly whisked eggs to make a soufflé. Get them out of the fridge and separate the yolks from the whites (this is easier when they are cold). Let the whites come to room temperature (cold egg white will not whisk well). The slightest trace of fat will prevent the egg whites whisking properly, so use a very clean and dry glass or metal (copper is classic) bowl.
Whisk the whites gently at first, then more vigorously until they have tripled in volume. At ‘soft peak’, the peaks on the egg white will flop; at ‘stiff peak’, only the very tops will flop.