DIAGNOSIS The cooker is timing out because it's taking too long to come to pressure. The most common reason is insufficient liquid, but it could also be a bad seal or too much food blocking the steam channel.
FIX First, verify you have at least 1 cup of thin liquid. Next, ensure your sealing ring is clean and properly seated, and the lid is locked (arrows aligned). Don't overfill—this 6-quart model should not be filled past the 2/3 line for most foods.
IF THAT DIDN'T WORK Check the float valve. If it's clogged with food, it won't rise, and the cooker won't recognize it's pressurized. Clean it by pushing it up and down under running water.
HEADS UP Starting with frozen ingredients or a very cold pot will drastically increase the time to come to pressure and can trigger this timeout. Thaw ingredients first or add a few extra minutes of pre-heat time on Sauté.