1. Insufficient baking powder: If too little baking powder is used when making dough, the carbon dioxide released by the baking powder is limited, and the dough is likely to be smaller or unable to rise. It is generally recommended to put about 10 grams of baking powder into one pound of flour.

2. Too little water: Baking powder needs to be exposed to moisture before it reacts and releases carbon dioxide. Therefore, if too little water is added, the dough may not rise.

3. Insufficient temperature: Using baking powder to make dough requires placing the dough at a higher temperature. Insufficient temperature may also cause the dough to fail to rise.

4. Wrong choice of baking powder: Baking powder is divided into fast reaction baking powder, slow reaction baking powder and double reaction baking powder. When fermenting the dough, try to use dual-reaction baking powder so that the dough will rise quickly and fluffy.