Update:
My booking through cheaptickets.hk also just got canned:
Why was my booking cancelled?
We could not guarantee ticketing on the flights you selected. Cheaptickets is a US-based travel agency, and certain itineraries (particularly some that originate outside of the US and Canada) may not be able to be processed through our automated ticketing system.
Amex did authorize some pre-auths from the merchant so the issue wasn't on my end. Looks like this thing is dying ?!