What specific things can the state governments not do according to articles of confederation?

State governments cannot engage in treaties or foreign affairs on their own, they cannot deal with currency as they want, and they can't organize their own armies.

I believe the answer is:

-send an embassy of make an alliance or treaty with another country

-accept presents, offices, or titles from another country

-make treaties between states

-engage in war w/o consent of Congress.

All the actions above can only be done by the federal government. The states' government is limited to only those that involved their own perspective states. The actions that written above would impacted the whole nation, so it should fall under federal jurisdiction.