Why was the Macedonian conquest of Greece possible?

This is due to the fact that in the 4th century BC, the position of Macedonia in the Balkans was significantly strengthened. The ambitious king Philip 2 came to power, who reformed the Macedonian army, and therefore, it became a formidable force. This became the reason that during the Greco-Macedonian war, Greece was defeated, moreover, it was not united. So in this war, Athens did not support Sparta. In this connection, most of Greece was captured by Macedonia.