What problems in the Ottoman Empire led to its decline?

One problem may have been was Muhammad death in A. D. 632. Muslims disagreed about choosing the successor. One group believed the successor must be someone along his bloodline, but he never had a son. That group rallied for his Son-In-Law, Ali, and Ali's descendants and his supporters were called the Shia Ali (Referred as Shi'ites) or Shi'ahs. Others said that it was worng for leadership of Islam to stay in Muhammad's Family bloodline.