Apple Pay Not Working in Big Sur

Solution ....  Into recovery mode - in the Startup Security Utility, I had Full Security and Disallow External Drive Booting selected, but Firmware Passord was not enabled. After enabling this Apple Pay is working again on my iMac PRO.

I too had the same issue. The reason for me was due to the fact that I had earlier disabled CSRUTIL during one of the software installations and not enabled it back. Turning it back on helped.

To do this, restart the machine, when the Apple logo appears, press CMD-R to get to Recovery Mode, launch Terminal from Utilities menu, and type the command CSRUTIL enable.

Open Startup Security Utility

1. Turn on your Mac, then press and hold Command (⌘)-R immediately after you see the Apple logo. Your Mac starts up from macOS Recovery.
2. When you're asked to select a user you know the password for, select the user, click Next, then enter their administrator password. 
3. When you see the macOS utilities window, choose Utilities > Startup Security Utility from the menu bar.
4. When you're asked to authenticate, click Enter macOS Password, then choose an administrator account and enter its password.

I have a similar issue on MacBook Pro 2018. After a clean install of the Big Sur it stopped working.

It redirects me to this KB: https://support.apple.com/en-gb/HT209016 and even after changing the settings it still doesn't work

I have the same issue - Interestingly the other issue that started at the same time is that the clipboard no longer transfers between my Mac and iPhone. Feels like it may be linked in that the connection between the devices (or the auth for it) may be broken.

I have the same issue.. Tried using your exact setting in Startup Security Utility, but it did not work for me. I have had a ticket open with Apple for over a month and still not resolved. I heard it's a problem with computer that have a T-2 chip, like your iMac and my MBPro.. Thanks for your help...

Yes the same here ..... iMac Pro, Big Sur 11.0.1 .... Apple Pay no longer works!!!!

Still doesn't work .... Apple must do update nad resolve this.

I'm glad it helped ...

Wow, I totally forgot I disabled System Protection to use CDock. Re-enabled it and now all is good. Thanks for this. No more CDock thou.. Oh well..