1. It was too harsh on Germany. The treaty imposed huge reparations on Germany, which crippled its economy and led to widespread unemployment and poverty. This in turn contributed to the rise of Adolf Hitler and the Nazi Party, who promised to overturn the treaty and restore Germany's greatness.
2. It failed to address the issue of German nationalism. The treaty left millions of ethnic Germans living outside of Germany's borders, which created resentment and a desire for revanchism. This eventually led to the outbreak of World War II.
3. It was not effectively enforced. The Allied Powers did not do enough to ensure that Germany complied with the terms of the treaty. This allowed Germany to rebuild its military and eventually violate the treaty.
4. It did not create a lasting peace. The Treaty of Versailles was supposed to prevent another world war, but it failed to do so. In fact, it arguably made the situation worse by creating the conditions that led to the rise of Nazism and the outbreak of World War II.