yubikey verification on google (firefox)

I've had a yubikey for some time I've used successfully to authorize a google
business account on a laptop running ubuntu.  On the laptop, firefox pointed
at google prompts for the yubikey after entering id/pw, then verifies ok.

On my fbsd workstation firefox pointed at google prompts for the yubikey after
id/pw, but I don't get any response.  The yubikey blinks but that's it.

I've got pkg_yubico installed, and user mounts on usb are allowed.

ykinfo -a
displays the info fine.

I'm not necessarily interested in modifying the key on fbsd; only using it.

$ uname -a
FreeBSD breakaway.dreamchaser.org 13.4-RELEASE-p3 FreeBSD 13.4-RELEASE-p3 GENERIC amd64

What am I missing?

Thanks,

Gary