What was the name of the united states’ 1st constitution? why did it not work?

America's first Constitution was called the Articles of Confederation. 

They did not work because of their various weaknesses:

-Each state only had one vote in Congress, regardless of size.
-Congress did not have the power to tax.
-Congress did not have the power to regulate foreign and interstate commerce.
-There was no executive branch to enforce any acts passed by Congress.
-There was no national court system or judicial branch.
-States could levy tariffs on other states' goods.

Basically there was no organization of government, and this was mainly because the Articles of Confederation were initially based on wartime urgency and was largely composed by a body that focused primarily on fighting and winning the War for Independence.