Why did the development of the military machine of the Ottoman Empire stop? (XVIII century)

This can be explained by the fact that, if in the first half of the 18th century, the Ottoman Empire was able to achieve certain military successes, which made it possible to maintain access to the Black and Azov Seas. At the same time, in the second half of the 18th century, it suffered a number of serious setbacks, which negatively affected the further state of the empire and ultimately led to its collapse.