The Articles of Confederation failed because of the lack of a strong central government. The Articles had a number of weaknesses that caused them to be rewritten and turned into the current U.S. Constitution.
One of the biggest weaknesses of the Articles of Confederation was that power was only granted to the central government on a goodwill basis from the states. The money produced under the Articles did not hold its value and brought the economy down to the verge of collapse. There was no proper taxation or individual judiciary branch, which made things more difficult on any attempt to run and maintain any form of central government.