Issue:
The customer experienced issues with YubiKeys, specifically related to certificate problems that affected their functionality.
Cause:
The underlying cause of the issue was identified as a misconfiguration of the certificates on the YubiKeys. It was suspected that the affected users had mistakenly selected the iKey setting instead of the PIV Card setting, which led to the need for the certificate to be recreated to clear the iKey cache.
Resolution:
Reprogram the affected YubiKeys to ensure they are correctly configured.
Verify that the correct settings (PIV Card) are selected instead of iKey.
After reprogramming, test the functionality of the YubiKeys to confirm they are working properly.
If issues persist, consider reprogramming any remaining devices and testing them as well.