Why did Napoleon want to stop British goods from reaching Europe?

Napoleon was able to conquer continental Europe due to his superior army and tactics. However the French Navy was inferior to the British Navy so he could not easily invade and defeat Britain.

Britain, meanwhile, was free to aid the enemies of Napoleon in Europe by subsidising them and sending them supplies.

Napoleon attempted to destroy Britain by destroying its trade. He forbade any country under his control to trade with Britain or accept British goods. This would deprive the British of their revenue and, he hoped, force them to stop supporting his opponents in Europe.

The strategy was ultimately unsuccessful.