Like HM said these Waldes zips can be finicky. The male pin needs to go all the way down for the first teeth to lock in.
However if this still doesn’t work then it’s probably a faulty zip. Seller should have disclosed this as zip replacement is not cheap. And if this is the case I’d get with the seller first. This jacket was from Grail right?
Fit looks really good! The Japanese jackets are cut very very trim. Looks really good though.