The team is trying to resolve these intermittent problems with publishing and preflighting. There is also a new release (2016.1) being deployed today, which could have some effect. Sorry about the inconvenience.
Any chance you guys could turn off the AUTO PREFLIGHT / PREVIEW on 'save' of a new layout? Sometimes gets in the way of editing and saving new layouts. Would prefer to work on several layouts and cards etc, and then preview in one go.
So while the preflight preview is taking so long - no layouts or cards can be saved. 'Try Again' does not work This is a massive bug and pain. Just lost a whole layout with card designs and settings. Infuriating.