The Morant Bay Rebellion occurred, of course, in Jamaica. However, I believe that this question is referring to the American Civil War. In my answer, I will assume that the economic crisis you mention was in Jamaica and that it and the American Civil War helped to bring about the Morant Bay Rebellion.
The American Civil War helped to cause, or at least to exacerbate, the economic crisis in Jamaica in the 1860s. Jamaica’s major product was, of course, sugar. During the 1850s and 1860s, world sugar prices were low. Jamaicans were making less money and were having to spend more of it because of things like high import duties on things that they had to bring in from the outside. The Civil War made this worse because the American South was a market for Jamaican products. One aspect of the North’s strategy was to institute a naval blockade of the South. This prevented goods from Jamaica from getting to their markets in the South. This further squeezed Jamaicans, causing more economic hardship.
It was largely the economic hardship that led to the Morant Bay Rebellion. As rural Jamaicans became poorer and more desperate, more of them resorted to theft. This led to more of them being jailed. The Jamaican government showed little interest in doing anything to help the impoverished people. This led to unrest among the poor and to anger on the part of people like George William Gordon, who advocated for them. It was this unrest that led to the rebellion.
Thus, the Civil War in the US helped make the economic crisis in Jamaica worse. This crisis led to the Morant Bay Rebellion.