The United Nations is an international intergovernmental organization established in 1945. Its task is to maintain international peace and security. All the nations are party to it. It is a wide organization which works through a formal and systematic arrangement. This is the foremost problem because of the wide structure and no single central entity whereas the Secretary-General can only try to coordinate the work of different agencies and committees formed under the UN.
Its structure is outdated I.e., the five countries U.S., Russia, China, Britain, and France have been the permanent members since 1945 when it had only 51 member states, now it has over 193 countries which result in lack in the representation of all nations.
The Funding of UN is unreliable as apart from nation states to contribute obligatory funds it requires financial resources to keep agencies and missions active. Nation states are defaulting in funding programs.