The most common problem encountered when learning the second jhāna results from the fact that the sukha is a more subtle object than the pīti of the first jhāna. It takes a more concentrated mind to be able to stay with this more subtle object. It sometimes happens that you generate strong enough access concentration to be able to enter the first jhāna, but when you move on to the second jhāna, you soon fall out of it. The solution is to stay longer in access concentration and let it deepen before moving to the first jhāna.
