Website error booking ticket with partner segment
I'm trying to book a ticket that includes one segment on ANA, and keep getting the error message "We’re sorry, but united.com was unable to complete your request. Please try later or contact united.com Support in the U.S. and Canada at 1-800-396-1751." When I called, the phone rep told me that the problem is the ANA segment, and that I should book an itinerary that includes only UA flights. I didn't find that very helpful (there aren't any UA-only itineraries that work).
Has anyone seen this before? Any suggestions for how to resolve it? I'm guessing HUACA, but thought I'd check quickly here first.
In case it matters, the itinerary was a paid business class roundtrip from the US to TPE.