I saw award space (also visible on BA Avios) but see the below error. I've already transferred 180K points from Amex, and am really worried now. Any advice? I'm on hold with Cathay for the phone, but it's been a long while.

We are unable to confirm the fare for the flights you have selected. Please choose a different fare or flights and resubmit your request. (15012 - 104)