How can apple pay cash be tested in a sandbox icloud ?

My device is logged into the apple pay sandbox icloud account created in itunesconnect and its region is set to United states. I am able to add Visa, Mastercard and Discover cards and use them successfully. However, when adding an amex card, it stays in "Activating" for a minute or two, then changes to "This card cannot be used". Please see the screenshot here (prefix with https): postimg.cc/LJMTHmf8 I have tried every possible thing I could think of to resolve it with no success including: creating a new icloud sandbox adding the card with sim installed/without sim installed factory restored the phone changed region to other country then back to US It does seem like something is down at apple/amex side, but no way to report it. Looks like at least 1 other person posted about experiencing the same issue - https://developer.apple.com/forums/thread/129869?answerId=666042022#666042022 Can anyone help?