Just got an error message immediately after click the Complete purchase button - in the sense - We are sorry. We are unable to process the order. Either try again later or use another payment card.
Card is an AMEX in profile.
No authorization is made.
Seems like either AMEX or GCM system is having issues - more like GCM's issue because just used another AMEX card at grocery shopping / restaurant less than 30 min ago.