Why did China stop exploring and contract (shrink) its trading empire after the death of the Yongle

Why did China stop exploring and contract (shrink) its trading empire after the death of the Yongle emperor (aka Zhu Di)?
麻烦各位历史高手们回答一下了，谢谢

Why China named China? 脑筋急转弯 Why did little Tom put his brother’s guitar in the refrigerator why so many ppl think China is a threat to U.S?? why did you leave me Why did you leave me China's是什么意思？ Chinese China's china可不可以加S China's Weakness Why did the Articles of Confederation fail?