The Articles of Confederation did not provide for a strong enough national government.
The Articles of Confederation did not allow for a federal military power and therefore there was no way to stop internal rebellion.
The Articles of Confederation had limited central power and was not able to have a standing army. Each state had a militia and when defense was needed the Congress needed to request the help of the states to defend the confederacy. In cases of such rebellions, states did not want to interfere and therefore refused to offer their militia to help.
