
bppcj (bppcj) asked a question.
Guys, I removed a Yubikey but forgot to refactor before removing it. Then I refactor the user associated to the key and removed it successfully. Now the Yubikey serial is no in Okta any longer and does not allows to add from the seeds csv file. I tested the format and it is the same we used hundreds of times. Any idea on how to fix it? Is there any 'Yubikey importation' log?

If a Yubikey is decoupled from it's user, consider revoking the token from your system and reissuing the end user another unassigned Yubikey for enrollment.
Everything that you can do in this particular scenarios would be to delete the MFA and set it back from scratch. I would recommend opening a ticket to support and maybe also attach a screenshot with the error for a more in depth understanding of the issue.
Thank you Orin, unfortunately I did both. Removed he user and also removed the key, but since then I'm not able to add it. Support request ended up in a link with very basic instructions on how to remove a Yubikey and readd it.