Why was it difficult for Congress to fund its operation?

Congress relied on contributions from the states, is the right answer.

Explanation:

Under the Articles of Confederations, the Congress was provided with very limited authority. The main reason for this was that the recently independent states of America did not want the government to dominate all the spheres of states. They feared that the concentration of power in the hands of the central government which may lead it to establish its tyranny as the British once had.

Because those people were very selfish they only thought about the corruption they never thought for the welfare of peple and development of the country so the citizens didn't like them. I think that's the reason to habe difficulties for congress to fund its operation