The Treaty of Versailles caused problems in the future because it treated Germany in a very harsh manner. The people of Germany were angered by the harsh and, in their minds, unfair treatment. In addition, the treaty weakened the German economy, leading to economic problems that also angered Germans. Overall, the treaty made Germans angry and made them more susceptible to supporting radicals like Hitler and the Nazis.
The Treaty of Versailles tried to destroy Germany as a strong country. It attempted to make Germany weak so that it could not threaten the other countries of Europe again. It did this by saying that Germany could not have a large military that had weapons that could be used for offensive purposes. It did this by taking territory from Germany and giving it to other countries. It did this by forcing Germany to pay reparations for the damages caused by World War I. In addition, though this did not weaken Germany, the treaty forced Germany to admit that it had been solely responsible for the war.
Because the treaty weakened and humiliated Germany in these ways, many Germans were very angry about it. They wanted Germany to return to power. They wanted it to reclaim its rightful position as a strong and important country. Because of this, they were willing to listen to radicals like Hitler as long as those radicals promised to get Germany back to its rightful place. In this way, the Treaty of Versailles led to the rise of Hitler and the Nazis. This is how it caused problems in the future.