Why did the scheliffen plan fail?

The Schlieffen Plan failed primarily due to underestimating the response and resilience of both Belgium and France, which slowed down the German advance. Additionally, the rapid mobilization of Russian forces in the East forced Germany to divert troops away from the Western Front. Poor logistics, communication issues, and the unexpected strength of Allied counterattacks, particularly at the First Battle of the Marne, further disrupted the plan, leading to a prolonged stalemate in World War I.