Needs More Time Proper fermentation requires time. Yogurt takes anywhere from 6 to 12 hours to set. You may just need to let it ferment (incubate) for a bit longer. If you're using a brand other than Fairlife or if you're using organic milk, you might need to add a few hours to the fermentation time e.g. 12 hours of fermentation. Starter Too Old If you're using an opened container of commercial yogurt, it could be too old. The longer an open container of yogurt sits in the fridge, the weaker the live cultures. Starter Not Potent If you're using yogurt set aside from a previous batch (recultured yogurt) it can start to be less effective after a few generations. At that point, you should buy a fresh container of starter yogurt. Using the Less Setting The Instant Pot Yogurt smart program has multiple settings. Some models have three settings: Less, Normal and More. The Less setting is for Jiu Niang (fermented glutinous rice) and won't work for yogurt. The More setting is for boiling the milk (used with regular milk). For this Instant Pot yogurt with Fairlife, you need to use the Normal setting which is for fermentation. If you've accidentally used the Less mode, switch it to Normal and start the fermentation again. Quantity of Starter Too Little You may have added too little of the yogurt starter. You'll probably end up with a good result if you let it ferment for a bit longer. Quantity of Starter Too Much You may have added too much starter. A heaping tablespoon of yogurt per quart (4 cups) of milk is enough. Although you might think that more is better, this isn't quite true. In fact, less is more. If you add too much starter, you'll crowd out the bacteria and it will run out of food to ferment. You can end up with runny yogurt. Wrong type of milk You may have used regular pasteurized milk and not ultra pasteurized milk. If you want to use pasteurized milk, you need to use the method used in my Instant Pot yogurt recipe where you boil the milk first. Inner Pot isn't Clean The Instant Pot inner pot could be contaminated. Always make sure that you start the fermentation in a clean and sterilized inner pot. Also make sure that any utensils you use are clean and dry. And watch out for soap residue. Instant Pot is Running too Warm or too Cold Measure the temperature of the milk/yogurt in the Instant Pot and make sure it's at approximately 110 degrees Fahrenheit. If it's much higher or lower, you may be using the Less or More setting or there may be an issue with the Instant Pot.