What is the ruling on a mosque imam who reads palms, and is it permissible to pray behind him?

Reading palms and coffee cups is forbidden and is an act of soothsayers who claim to know the unseen, which is an act of disbelief (kufr). It is not permissible for an Imam to practice soothsaying or to visit soothsayers and believe them. In the Hadith: "Whoever comes to a fortuneteller or soothsayer has disbelieved in what was revealed to Muhammad." The least severe condition for someone who commits these acts is فسق (moral transgression).