The issue was identified and resolved. Launching new instances and launching from snapshots now works correctly. Thanks for your patience.
Posted Aug 15, 2016 - 19:18 PDT
Update
Launching new instances now works correctly, but launching instances from snapshots is still unavailable. Running and paused instances are not affected.
Posted Aug 15, 2016 - 17:36 PDT
Identified
It is currently not possible to launch new instances - we are investigating. Running and paused instances are not affected.