Britain and France were in a war and were interfering with American trade. This hurt the neutral side America was trying to take. Britain was blocking French ports and France did the same.
The Embargo Act :
Many people in the British navy left because of bad conditions, so they snuck on board American trade ships trying to go there for freedom. So Britain started searching the ships for the people trying to leave called deserters and Britain impressed those they found leaving along with some American crew members .
A British Warship called Leopard stopped the American ship the Chesapeake, and when the captain demanded the boat should be search and they refused so Britain opened fire and killed three people. When news got back to America they were as mad at Britain as they were before the Revolutionary war.
The act prohibited trade with all foreign countries' imports and exports and was put in place to stop trade with Britain to punish them, but still not take sides. This did not work well because Britain can buy its goods from other countries and America had to make everything, prices of crops went down and people who worked in the harbor were losing their jobs.
White settlers wanted more land in the Ohio River Valley. The Native Americans had already given up millions of acres and American settlers were moving onto lands given to the Native Americans by treaty. They believed the treaties were worthless. So Native Americans started renewing contracts with British agents wanting an alliance with backing Britain.
War Hawks are a group of young Republicans in congress. They wanted land in southern Canada, and Native Americans wanted an alliance with Canada. The people from southern Canada wanted Spanish Florida. War Hawks wanted to expand the native's power. They also supported increases in military spending, driven by hunger for land.