Originally Posted by
GVDM
I know you can't magician LX-flights, but I am just curious to find out WHY the return flight on LX-metal won't work.
Either there's no availability on the UA codeshare or the search just didn't find that particular combination.
Google Flights, as already suggested, might work; otherwise, try multi-city search on the United website. UA's flight search engine doesn't find every possible combination of flights.