Answer:
The reason why the promise of "40 acres and a mule disappointed many newly freed African Americans.
Was because, after the death of former president Abraham Lincoln, President Andrew Johnson mandated to reverse ownership of land from African Americans, and offered only payment for the work of the land.
Step-by-step explanation:
When former president Abraham Lincoln was alive he made the promise. However when he died and Andrew Johnson replaced him. He just backed it up and blocked African Americans from owning the land. Instead, he offered them payment. Also, most African Americans obtained land through a private transaction. They were disappointed because the government failed its promise.