I errored on my state estimated payments (overstated by $500). It recalculated that I owed $60 for federal. Won't let me file ammended federal, only state.

I errored on my state estimated payments (overstated by $500).  The State caught it just fine and paid me $500 less without needing to amend the state.  I went back into my taxes to file an ammended retrun for Federal.  I adjusted the payments and it recalculated that I owed $60 for federal.  I went to file and it only allows me to file an ammended state return ... not the federal return.   What do I do?