Why did the Sepoy soldiers mutiny against the British in 1857?

The league of nations was found in 1919 to keep peace after world war l.but it failed to prevent world war ll in 1939,so in 1945 the nations of the world set up a new organization,the united state (un).since then, the un has encouraged international cooperation and worked to resolve conflict

Tbh i dont know the answeererrr im hust answering