Why was nana sahib not acknowledged as the rightful heir to the throne?

Nana Sahib was not acknowledged as the rightful heir to the throne of the Maratha kingdom because he was the adopted son of the late Peshwa Baji Rao II, and the British East India Company did not recognize adopted heirs under their policy. After the Peshwa's death in 1851, the British annexed the territory, asserting that the Peshwa had no legitimate biological heirs. Nana Sahib's claims were further complicated by the broader political context and the British desire to consolidate control over Indian territories. This lack of recognition ultimately led to his involvement in the Indian Rebellion of 1857.