I was quite worried at PVG today when I couldn't initially get the Alipay DiDi mini app to work, despite setting up Alipay with two bank card options (US credit cards) and uploading my passport in the Identity Verification section. The error it gave was Prepayment Failed and then another screen popped up about missing Identity Verification. I checked again in Alipay Settings and saw the verification was still completed. As a result, I tried requesting the DiDi again, and that time, everything worked as intended, and an Alipay screen came up for me to enter the passcode I set and select the bank card for the prepayment.

So, lesson learned, try again :-)