Have been using the ANA seat availability search engine today (under "Partner Flight Awards"), putting in various pairs of US cities (Phoenix, Seattle, Houston, Honolulu, and others) and various dates (some 11 months out, some 6 months out, some one month out) trying dates in various months.

With each search, however, this message has come up: "We are sorry to inform you that there are no applicable direct or connecting flights".

Is there something I should be doing differently? Or are US domestic flights hard to book using ANA miles for some reason?