@mods please can you tell me how to resolve July 4 as No?

you can't unfortunately

all options in a linked MC market must stay open until the entire market closes or resolves

I have seen it done on other markets. What did I do wrong?

those were probably unlinked markets, meaning they don't sum to 1

Ah, should I close as NA and make a new market?

No, it is fine as it is. you can see a similar market like https://manifold.markets/DismalScientist/what-day-will-biden-drop-out where the options before july 5 are at 0.1% or something. they can't be resolved early but nobody's buying them so it doesn't matter much