Many people felt that Germany had received a very harsh deal in the Treaty of Versailles and they resented the government for signing it and agreeing to its conditions. Germany was required to:
Accept full responsibility for the causing the war (article 231) and therefore the devastation and losses of the war.
Pay reparations of £6,600 million for the damage caused, and give the coal mines of the Saar area to France as compensation for destroying the coal mines of northern France.
Lose land. They had to give Alsace-Lorraine to France, and a Polish corridor was created to prevent Poland being landlocked but separated East Prussia from the rest of Germany. They lost control of all foreign colonies and Germany was forbidden to unite with Austria.
Limit their military power, with an army of no more than 100,000 members and only small ships in the Navy. The Rhineland was demilitarised.