Originally Posted by
demue
That is crappy and should not be happening. Singapore issued Amex cards support Amex Safe Key and should definitely work. Last time I used one has been years ago though as these days I use other cards.
The weird thing was, the screen took me all the way to the Amex Safe Key site, i got my OTP from Amex and filled it in accordingly, but once I submitted that page, and the SQ confirmation page was supposed to load, it didn't, and gave me the error instead. So I suspect it was really SQ's error rather than Amex or the cards.