Why aren't you opening the AMZN market? I placed a short order at 575, and it didn't execute (not because the market's price was lower, but because the markets didn't open on 1Broker)...
Hopefully, this is just a technical security measure, and not an attempt to do something wrong.

I know that the ToS doesn't offer a refund for unopened positions, but this seems to be a special issue right now, and can also be considered as an unscheduled outage. I'd be respectful to the development team whether they handle the situation professionally, like anytime else.
EDIT: I was finally able to execute a short at 560.44 (position ID: AMZN-332110). I couldn't wait for the official statement about the issue...