There may be a couple of reasons your instant pot yogurt didn't set properly: 1. You didn't use the right starter. Make sure the starter you use has active cultures. 2. It didn't boil correctly. The "YOGURT" button on your instant pot should take care of this, but to be safe you can check that the milk boiled to 180ºF or higher. 3. Chill before adding the starter. Make sure you cool the milk to 110-115ºF before you add the starter. 4. You didn't chill long enough. Chill the finished yogurt for 6-8 hours in the fridge after it incubates. This allows it to thicken into that classic yogurt consistency.