Apple Pay not working for online purchases on iPhone Air and MacBook Pro

New iPhone Air. Have credit and debit cards in Wallet and all have been verified but online purchases using Apple Pay do not work (displays an exclamation mark). Signed out of iCloud account which removed all cards so added again and finally got all cards verified but Apple Pay still not working.

Tried to make purchase on MacBook Pro to eliminate an iPhone specific problem but same result - Apple Pay payment does not go through... does not quite get to the fingerprint authorisation. Tried alternative cards to eliminate any problem with a particular card but the result is the same. Checked Apple website and there is no problem flagged with Apple Pay.

I am running iOS 26.0.1 on iPhone and Sequoia 15.7.1 on Mac.

No problem of course making a purchase not using Apple Pay.

If I contacted Apple support I am sure I will go round in the same circles - anyone else having problems or can suggest a way out that doesn't involve going to an Apple store?

[Re-Titled by Moderator]

Original Title: Apple Pay not working