ApplePay Payment not Completed in Safari on macOS

Every time I try to use my Apple Card in Safari for macOS, I go through all the motions, use Touch ID (which works), and then get the error "Payment not Completed," and I'm back at checkout on that particular web site. It's all web sites that take ApplePay, not just one or two.

I've verified that my billing address is correct, and tried again, but that doesn't work.

ApplePay works fine on the same web sites from my iPhone or iPad. Just not in macOS.

What else should I try to resolve this? Suggestions welcome!