Why did Tiberius wait before accepting the title of emperor from the Senate?

Following the death of Augustus on August 19, 14 ce, Tiberius did not immediately accept the title of emperor. Instead, he engaged in political maneuvering with the Senate and delayed his formal succession for nearly a month, finally assuming the principate on September 17.12

This hesitation was largely due to the fact that the "principate" established by Augustus was not, constitutionally speaking, a heritable or continuous office. Because the position lacked a formal legal framework for succession, the transition created an embarrassing and complex situation for both Tiberius and the Senate. By delaying, Tiberius navigated the delicate political reality of succeeding a ruler whose power was absolute in practice but maintained under the guise of republican tradition.23