Originally Posted by
flyquiet
That looks like travel agent witchcraft. I often have to book YYZ-US (stop) US-US (stop) US-YYZ trips and can never do it as a multi city on AC website. The multi city tool on AC website coughs up "It is not possible to search for flights which have both an origin and a destination in the United States." (red font in original.) If I am missing the secret password to making it do it, I'd love to know it.
If you repeatedly try to commit sabotage on AC, you risk repercussions.
If any word in that statement is incorrect, I apologize. I learned it from people who work at the airport.