why did the articles of confederation not work effectively?

Under the Articles of Confederation, states retained their freedom and independence. Each of the 13 states had a vote in the weak national Congress (appointed by the stategovernments), while a vote of 9 states was required in order to pass any laws and a unanimous vote of all 13 states was required for the Articles to be amended. The national Congress was also denied the power to tax, so it could not pay for the army and navy needed to defend the nation.
The result of this decentralized approach was that each state functioned in many ways as
an independent country. Several states negotiated their own trade agreements with those
countries that the king had previously convinced not to have a relationship with the colonies,
while other states established their own militaries. The result of these state actions was that the
states did not function as a nation. Fears emerged that 13 states functioning as independent
countries would make the nation vulnerable.

Together the lack of powers held by the weak national Congress coupled with each
state’s independent and often conflicting actions, raised concerns that the Articles of
Confederation were not designed in a way to protect the new nation

They didn't create a strong enough organization. You have to have a strong central commitment in a large group, otherwise it's more like a country club where people know each other, but it's more casual and they aren't working together as much.

Who said they didn't?
Were they really given a chance?