If your milk is not foaming, it could be because the milk itself has gone bad, the temperature of the milk isn’t warm enough or there is too much fat content in the milk.
It’s also possible that you are not whisking or steaming correctly – make sure to whisk vigorously and steadily until you achieve a thick foam with a gloss-like sheen on top. You may need to adjust the temperature or experiment with different types of milks to find one that works best for you.
