Which was not a weakness of the articles of confederation?

no national court system was established.
congress had no power to control trade.
national government was given too much power.
congress lacked the power to tax.

The answer is actually "No national court system was established", because there was a court system in place but it left to Congress the authority to create lower federal courts as needed, giving them too much power. So that would mean that, that was not a weakness because they had one so no problem there.