If you are on ubuntu and/or your web browser is installed via snap and you use yubikey or any other physical 2fa device, there is a chance that the key suddenly stops working. It might not be broken as there seems to be a bug in snapd v2.62.
I went to report it but someone already has done that (https://bugs.launchpad.net/snapd/+bug/2062148)
The solution is to downgrade your snapd (at least at the moment).
Check what versions you currently have installed:
If you are not currently using snapd 2.62, then you might want to stop and investigate the issue further (or downgrade nevertheless to eliminate snapd as culprit)
List available ones
Name Version Rev Tracking Publisher Notes
snapd 2.62 21465 latest/stable canonical✓ snapd,disabled
snapd 2.61.2 21184 latest/stable canonical✓ snapd
Note the revision numbers, in this case we want to use 2.61.2 with revision number 21184. Yours might differ.
Downgrade
You might have to (however in my case it was not necessary) relaunch the affected web browser for this change to take effect.
Hope this helps!
