At first it is difficult to understand why Germany would have accepted the Treaty of Versailles.
The armistice had been agreed upon 11 November 1918 and was explicitly based on the terms of Wilson's Fourteen Points and the Germans made it clear that they were ceasing hostilities based on the assumption that those terms would be the basis for a future treaty.
Nevertheless, this did not happen. There was no treaty until 28 June 1919, more than seven months later, and when this treaty was signed it was highly unfavorable to Germany and completely abrogated the Fourteen Points.
Why would Germany ever have agreed to this?
The only explanation I can think of is that England, France and Italy must have maintained a naval blockade on Germany and prevented any imports or exports from that country and essentially tried to economically starve them into signing the Treaty of Versailles. Was this the cause? If so, was Germany blockaded on only the North Sea (Hamburg), or was the Baltic Sea (Kiel and Danzig) blockaded as well? Obviously Germany could have traded with Holland and Denmark. Did England blockade Holland and Denmark, too?